Anti-agglomerants for polyisobutylene production

ABSTRACT

The invention relates to a method to reduce or prevent agglomeration of polyisobutylene particles in aqueous media by LCST compounds and highly pure isobutylenes obtained thereby. The invention further relates to polyisobutylene products comprising the same or derived therefrom.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a National Stage of PCT/CA2014/051249, which wasfiled on Dec. 22, 2014. This application is based upon and claims thebenefit of priority to European Application No. 14179577.9, which wasfiled on Jul. 7, 2014, and to European Application No. 14175025.7, whichwas filed on Jun. 30, 2014, and to European Application No. 14160738.2,which was filed on Mar. 19, 2014, and to European Application No.13199466.7, which was filed on Dec. 23, 2013.

FIELD OF THE INVENTION

The invention relates to a method to reduce or prevent agglomeration ofpolyisobutylene particles in aqueous media by LCST compounds and highlypure isobutylenes obtained thereby. The invention further relates topolyisobutylene products comprising the same or derived therefrom.

BACKGROUND

Rubbers in particular those comprising repeating units derived fromisoolefins are industrially prepared by carbocationic polymerizationprocesses. Of particular importance is polyisobutylene.

The carbocationic polymerization of isoolefins is mechanisticallycomplex. The catalyst system is typically composed of two components: aninitiator and a Lewis acid such as aluminum trichloride which isfrequently employed in large scale commercial processes.

Examples of initiators include proton sources such as hydrogen halides,alcohols, phenols, carboxylic and sulfonic acids and water.

During the initiation step, the isoolefin reacts with the Lewis acid andthe initiator to produce a carbenium ion which further reacts with amonomer forming a new carbenium ion in the so-called propagation step.

The type of monomers, the type of diluent or solvent and its polarity,the polymerization temperature as well as the specific combination ofLewis acid and initiator affects the chemistry of propagation and thusmonomer incorporation into the growing polymer chain.

Industry has generally accepted widespread use of a slurrypolymerization process to produce butyl rubber, polyisobutylene, etc. inmethyl chloride as diluent. Typically, the polymerization process iscarried out at low temperatures, generally lower than −90□ C. Methylchloride is employed for a variety of reasons, including that itdissolves the monomers and aluminum chloride catalyst but not thepolymer product. Methyl chloride also has suitable freezing and boilingpoints to permit, respectively, low temperature polymerization andeffective separation from the polymer and unreacted monomers. The slurrypolymerization process in methyl chloride offers a number of additionaladvantages in that a polymer concentration of up to 40 wt.-% in thereaction mixture can be achieved, as opposed to a polymer concentrationof typically at maximum 20 wt.-% in solution polymerizations. Anacceptable relatively low viscosity of the polymerization mass isobtained enabling the heat of polymerization to be removed moreeffectively by surface heat exchange. Slurry polymerization processes inmethyl chloride are used in the production of high molecular weightpolyisobutylene and isobutylene-isoprene butyl rubber polymers.

In a polyisobutylene slurry polymerization, the reaction mixturetypically comprises the polyisobutylene, diluent, residual monomers andcatalyst residues. This mixture is either batchwise or more commonly inindustry continuously transferred into a vessel with water comprising

-   -   an anti-agglomerant which may be for example a fatty acid salt        of a multivalent metal ion, in particular either calcium        stearate or zinc stearate in order to form and preserve butyl        rubber particles, which are more often referred to as □butyl        rubber crumb□    -   and optionally but preferably a stopper which is typically an        aqueous sodium hydroxide solution to neutralize initiator        residues.

The water in this vessel is typically steam heated to remove and recoverdiluent and unreacted monomers.

As a result thereof a slurry of polyisobutylene particles is obtainedwhich is then subjected to dewatering to isolate polyisobutyleneparticles. The polyisobutylene rubber particles are then dried, baledand packed for delivery.

The anti-agglomerant ensures that in the process steps described abovethe butyl rubber particles stay suspended and show a reduced tendency toagglomerate.

In the absence of an anti-agglomerant the naturally high adhesion ofpolyisobutylene would lead to rapid formation of a non-dispersed mass ofrubber in the process water, plugging the process. In addition toparticle formation, sufficient anti-agglomerant must be added to delaythe natural tendancy of the formed butyl rubber particles to agglomerateduring the stripping process, which leads to fouling and plugging of theprocess.

The anti-agglomerants in particular calcium and zinc stearates functionas a physical-mechanical barrier to limit the close contact and adhesionof polyisobutylene particles.

The physical properties required of these anti-agglomerants are a verylow solubility in water which is typically below 20 mg per liter understandard conditions, sufficient mechanical stability to maintain aneffective barrier, and the ability to be later processed and mixed withthe polyisobutylene to allow finishing and drying.

The fundamental disadvantage of fatty acid salts of a mono- ormultivalent metal ion, in particular sodium, potassium calcium or zincstearate or palmitate is their chemical interaction with componentstypically compounded with polyisobutylene to form sealants or adhesivesand further their insolubility in polyisobutylene which causes undesiredturbidity and optical appearance.

A variety of other polyisobutylenes either obtained after polymerizationor after post-polymerization modification in organic solution or slurryare typically subjected to an aqueous workup where the same problemsapply as well.

Therefore, there is still a need for providing a process for thepreparation of polyisobutylene in aqueous media having reduced or lowtendency of agglomeration.

SUMMARY OF THE INVENTION

According to one aspect of the invention, there is provided a processfor the preparation of an aqueous slurry comprising a plurality ofpolyisobutylene particles suspended therein, the process comprising atleast the step of:

-   A) contacting an organic medium comprising    -   i) polyisobutylene and    -   ii) an organic diluent    -   with an aqueous medium comprising at least one LCST compound        having a cloud point of 0 to 100□ C, preferably 5 to 100□ C,        more preferably 15 to 80□ C and even more preferably 20 to 70□ C        and-   B) removing at least partially the organic diluent to obtain the    aqueous slurry comprising the polyisobutylene particles.

DETAILED DESCRIPTION OF THE INVENTION

The invention also encompasses all combinations of preferredembodiments, ranges parameters as disclosed hereinafter with either eachother or the broadest disclosed range or parameter.

In one embodiment the organic medium comprising polyisobutylene and anorganic diluent is obtained from a polymerization reaction.

Where the organic medium comprising polyisobutylene and an organicdiluent is obtained from a polymerization reaction the medium mayfurther contain residual butylene of the polymerization reaction.

The aqueous medium may further contain non-LCST compounds, whereby thenon-LCST compounds are

-   -   selected from the group consisting of ionic or non-ionic        surfactants, emulsifiers, and antiagglomerants or are in another        embodiment    -   salts of mono- or multivalent metal ions or are in another        embodiment    -   stearates or palmitates of mono- or multivalent metal ions or        are in another embodiment    -   sodium, potassium, calcium and zinc stearates or palmitates

In one embodiment the aqueous medium therefore comprises 20.000 ppm orless, preferably 10.000 ppm or less, more preferably 8.000 ppm or less,even more preferably 5.000 ppm or less and yet even more preferably2.000 ppm or less and in another yet even more preferred embodiment1.000 ppm or less of non-LCST compounds, whereby the non-LCST compoundsare selected from the four groups above and are preferably calculatedwith respect to the amount of polyisobutylene present in the organicmedium.

In another embodiment the aqueous medium comprises 500 ppm or less,preferably 100 ppm or less, more preferably 50 ppm or less, even morepreferably 30 ppm or less and yet even more preferably 10 ppm or lessand in another yet even more preferred embodiment 1.000 ppm or less ofnon-LCST compounds whereby the non-LCST compounds are selected from thefour groups above and are preferably calculated with respect to theamount of polyisobutylene present in the organic medium.

If not expressly stated otherwise ppm refers to parts per million byweight.

In one embodiment the aqueous medium comprises of from 0 to 5,000 ppm,preferably of from 0 to 2,000 ppm, more preferably of from 10 to 1,000ppm, even more preferably of from 50 to 800 ppm and yet even morepreferably of from 100 to 600 ppm of salts of mono or multivalent metalions calculated on their metal content and with respect to the amount ofpolyisobutylene present in the organic medium.

In another embodiment the aqueous medium comprises of from 0 to 5,000ppm, preferably of from 0 to 2,000 ppm, more preferably of from 10 to1,000 ppm, even more preferably of from 50 to 800 ppm and yet even morepreferably of from 100 to 600 ppm of salts of multivalent metal ionscalculated on their metal content and with respect to the amount ofpolyisobutylene present in the organic medium.

In another embodiment the weight ratio of salts of stearates, palmitatesand oleates of mono- and multivalent metal ions, if present, to the LCSTcompounds is of from 1:2 to 1:100, preferably 1:2 to 1:10 and morepreferably of from 1:5 to 1:10 in the aqueous medium.

In one embodiment the aqueous medium comprises 550 ppm or less,preferably 400 ppm or less, more preferably 300 ppm or less, even morepreferably 250 ppm or less and yet even more preferably 150 ppm or lessand in another yet even more preferred embodiment 100 ppm or less ofsalts of metal ions calculated on their metal content and with respectto the amount of polyisobutylene present in the organic medium.

In yet another embodiment the aqueous medium comprises 550 ppm or less,preferably 400 ppm or less, more preferably 300 ppm or less, even morepreferably 250 ppm or less and yet even more preferably 150 ppm or lessand in another yet even more preferred embodiment 100 ppm or less ofsalts of multivalent metal ions calculated on their metal content andwith respect to the amount of polyisobutylene present in the organicmedium.

In one embodiment, the aqueous medium comprises 8.000 ppm or less,preferably 5.000 ppm or less, more preferably 2.000 ppm or less, yeteven more preferably 1.000 ppm or less, in another embodiment preferably500 ppm or less, more preferably 100 ppm or less and even morepreferably 15 ppm or less and yet even more preferably no or from 1 ppmto 10 ppm of non-ionic surfactants being non-LCST compounds selectedfrom the group consisting of ionic or non-ionic surfactants,emulsifiers, and antiagglomerants and with respect to the amount ofpolyisobutylene present in the organic medium.

As used herein a LCST compound is a compound which is soluble in aliquid medium at a lower temperature but precipitates from the liquidmedium above a certain temperature, the so called lower criticalsolution temperature or LCST temperature. This process is reversible, sothe system becomes homogeneous again on cooling down. The temperature atwhich the solution clarifies on cooling down is known as the cloud point(see German standard specification DIN EN 1890 of September 2006). Thistemperature is characteristic for a particular substance and aparticular method.

Depending on the nature of the LCST compound which typically compriseshydrophilic and hydrophobic groups the determination of the cloud pointmay require different conditions as set forth in DIN EN 1890 ofSeptember 2006. Even though this DIN was originally developed fornon-ionic surface active agents obtained by condensation of ethyleneoxide this method allows determination of cloud points for a broadvariety of LCST compounds as well. However, adapted conditions werefound helpful to more easily determine cloud points for structurallydifferent compounds.

Therefore the term LCST compound as used herein covers all compoundswhere a cloud point of 0 to 100□ C, preferably 5 to 100□ C, morepreferably 15 to 80□ C and even more preferably 20 to 80□ C can bedetermined by at least one of the following methods:

-   1) DIN EN 1890 of September 2006, method A-   2) DIN EN 1890 of September 2006, method C-   3) DIN EN 1890 of September 2006, method E-   4) DIN EN 1890 of September 2006, method A wherein the amount of    compound tested is reduced from 1 g per 100 ml of distilled water to    0.05 g per 100 ml of distilled water.-   5) DIN EN 1890 of September 2006, method A wherein the amount of    compound tested is reduced from 1 g per 100 ml of distilled water to    0.2 g per 100 ml of distilled water.

In another embodiment the cloud points indicated above can be determinedby at least one of the methods 1), 2) or 4).

In a preferred embodiment the LCST compounds are those which cloudpoints can be determined by at least one of the methods 1), 3) or 4).

As a consequence, non-LCST compounds are those compounds having eitherno cloud point or a cloud point outside the scope as definedhereinabove. It is apparent to those skilled in the art and known fromvarious commercially available products, that the different methodsdescribed above may lead to slightly different cloud points. However,the measurements for each method are consistent and reproducible withintheir inherent limits of error and the general principle of theinvention is not affected by different LCST temperatures determined forthe same compound as long as with at least one of the above methods thecloud point is found to be within the ranges set forth above.

For the sake of clarity it should be mentioned that metal ions, inparticular multivalent metal ions such as aluminum already stemming fromthe initiator system employed in step b) are not encompassed by thecalculation of metal ions present in the aqueous medium employed in stepA).

In another embodiment, the aqueous medium comprises 70 ppm or less,preferably 50 ppm or less, more preferably 30 ppm or less and even morepreferably 20 ppm or less and yet even more preferably 10 ppm or less ofsalts of multivalent metal ions calculated on their metal content andwith respect to the amount of polyisobutylene present in the organicmedium.

In yet another embodiment, the aqueous medium comprises 25 ppm or less,preferably 10 ppm or less, more preferably 8 ppm or less and even morepreferably 7 ppm or less and yet even more preferably 5 ppm or less ofsalts of multivalent metal ions calculated on their metal content andwith respect to the amount of polyisobutylene present in the organicmedium.

In another embodiment, the aqueous medium comprises 550 ppm or less,preferably 400 ppm or less, more preferably 300 ppm or less, even morepreferably 250 ppm or less and yet even more preferably 150 ppm or lessand in another yet even more preferred embodiment 100 ppm or less ofcarboxylic acid salts of multivalent metal ions calculated on theirmetal content and with respect to the amount of polyisobutylene presentin the organic medium, whereby the carboxylic acids are selected fromthose having 6 to 30 carbon atoms, preferably 8 to 24 carbon atoms, morepreferably 12 to 18 carbon atoms. In one embodiment such carboxylicacids are selected from monocarboxylic acids. In another embodiment suchcarboxylic acids are selected from saturated monocarboxylic acids suchas stearic acid.

The following example shows how the calculation is performed.

The molecular weight of calcium stearate (C₃₆H₇₀CaO₄) is 607.04 g/mol.The atomic weight of calcium metal is 40.08 g/mol. In order to providee.g. 1 kg of an aqueous medium comprising 550 ppm of a salts of amultivalent metal ion (calcium stearate) calculated on its metal content(calcium) and with respect to the amount of polyisobutylene present inthe organic medium that is sufficient to form a slurry from a organicmedium comprising 10 g of a polyisobutylene the aqueous medium mustcomprise (607.04/40.08)×(550 ppm of 10 g)=83 mg of calcium stearate or0.83 wt.-% with respect to the polyisobutylene or 83 ppm with respect tothe aqueous medium. The weight ratio of aqueous medium topolyisobutylene present in the organic medium would in this case be100:1.

In yet another embodiment, the aqueous medium comprises 70 ppm or less,preferably 50 ppm or less, more preferably 30 ppm or less and even morepreferably 20 ppm or less and yet even more preferably 10 ppm or less ofcarboxylic acid salts of multivalent metal ions calculated on theirmetal content and with respect to the amount of polyisobutylene presentin the organic medium, whereby the carboxylic acids are selected fromthose having 6 to 30 carbon atoms, preferably 8 to 24 carbon atoms, morepreferably 12 to 18 carbon atoms. In one embodiment such carboxylicacids are selected from monocarboxylic acids. In another embodiment suchcarboxylic acids are selected from saturated monocarboxylic acids suchas palmitic acid or stearic acid.

In yet another embodiment, the aqueous medium comprises 25 ppm or less,preferably 10 ppm or less, more preferably 8 ppm or less and even morepreferably 7 ppm or less and yet even more preferably 5 ppm or less ofcarboxylic acid salts of multivalent metal ions calculated on theirmetal content and with respect to the amount of polyisobutylene presentin the organic medium, whereby the carboxylic acids are selected fromthose having 6 to 30 carbon atoms, preferably 8 to 24 carbon atoms, morepreferably 12 to 18 carbon atoms. In one embodiment such carboxylicacids are selected from monocarboxylic acids. In another embodiment suchcarboxylic acids are selected from saturated monocarboxylic acids suchas stearic acid.

In one embodiment the aqueous medium is free of carboxylic acid salts ofmultivalent metal ions whereby the carboxylic acids are selected fromthose having 6 to 30 carbon atoms, preferably 8 to 24 carbon atoms, morepreferably 12 to 18 carbon atoms. In one embodiment such carboxylicacids are selected from monocarboxylic acids. In another embodiment suchcarboxylic acids are selected from saturated monocarboxylic acids suchas stearic acid.

In another embodiment, the aqueous medium comprises 100 ppm or less,preferably 50 ppm or less, more preferably 20 ppm or less and even morepreferably 15 ppm or less and yet even more preferably 10 ppm or less ofsalts of monovalent metal ions calculated on their metal content andwith respect to the amount of polyisobutylene present in the organicmedium.

In another embodiment, the aqueous medium comprises additionally oralternatively 100 ppm or less, preferably 50 ppm or less, morepreferably 30 ppm or less, even more preferably 20 ppm or less and yeteven more preferably 10 ppm or less and in another yet even morepreferred embodiment 5 ppm or less of carboxylic acid salts ofmonovalent metal ions such as sodium stearate, sodium palmitate andsodium oleate and potassium stearate, potassium palmitate and potassiumoleate calculated on their metal content and with respect to the amountof polyisobutylene present in the organic medium, whereby the carboxylicacids are selected from those having 6 to 30 carbon atoms, preferably 8to 24 carbon atoms, more preferably 12 to 18 carbon atoms. In oneembodiment such carboxylic acids are selected from monocarboxylic acids.In another embodiment such carboxylic acids are selected from saturatedmonocarboxylic acids such as stearic acid. Examples of monovalent saltsof carboxylic acids include sodium stearate, palmitate and oleate aswell as potassium stearate, plamitate and oleate.

In one embodiment the aqueous medium is free of carboxylic acid salts ofmonovalent metal ions whereby the carboxylic acids are selected fromthose having 6 to 30 carbon atoms, preferably 8 to 24 carbon atoms, morepreferably 12 to 18 carbon atoms. In one embodiment such carboxylicacids are selected from monocarboxylic acids. In another embodiment suchcarboxylic acids are selected from saturated monocarboxylic acids suchas palmitic or stearic acid.

In another embodiment the aqueous medium comprises of from 0 to 5,000ppm, preferably of from 0 to 2,000 ppm, more preferably of from 10 to1,000 ppm, even more preferably of from 50 to 800 ppm and yet even morepreferably of from 100 to 600 ppm of carbonates of multivalent metalions calculated on their metal content and with respect to the amount ofpolyisobutylene present in the organic medium.

In another embodiment, the aqueous medium comprises 550 ppm or less,preferably 400 ppm or less, more preferably 300 ppm or less, even morepreferably 250 ppm or less and yet even more preferably 150 ppm or lessand in another yet even more preferred embodiment 100 ppm or less ofcarbonates of multivalent metal ions calculated on their metal contentand with respect to the amount of polyisobutylene present in the organicmedium.

In yet another embodiment, the aqueous medium comprises 70 ppm or less,preferably 50 ppm or less, more preferably 30 ppm or less and even morepreferably 20 ppm or less and yet even more preferably 10 ppm or less ofcarbonates of multivalent metal ions calculated on their metal contentand with respect to the amount of polyisobutylene present in the organicmedium.

Carbonates of multivalent metal ions are in particular magnesiumcarbonate and calcium carbonate.

The term multivalent metal ions encompasses in particular bivalent earthalkaline metal ions such as magnesium, calcium, strontium and barium,preferably magnesium and calcium, trivalent metal ions of group 13 suchas aluminium, multivalent metal ions of groups 3 to 12 in particular thebivalent metal ion of zinc.

The term monovalent metal ions encompasses in particular alkaline metalions such as lithium, sodium and potassium.

In another embodiment, the aqueous medium comprises 500 ppm or less,preferably 200 ppm or less, more preferably 100 ppm or less, even morepreferably 50 ppm or less and yet even more preferably 20 ppm or lessand in another yet even more preferred embodiment no layered mineralssuch as talcum calculated with respect to the amount of polyisobutylenepresent in the organic medium.

In another embodiment, the aqueous medium comprises 500 ppm or less,preferably 200 ppm or less, more preferably 100 ppm or less, even morepreferably 20 ppm or less and yet even more preferably 10 ppm or lessand in another yet even more preferred embodiment 5 ppm or less and yeteven more preferably no dispersants, emulsifiers or anti-agglomerantsother than the LCST compounds. The term □plurality□ denotes an integerof at least two, preferably at least 20, more preferably at least 100.

In one embodiment the expression □aqueous slurry comprising a pluralityof polyisobutylene particles suspended therein□ denotes a slurry havingat least 10 discrete particles per liter suspended therein, preferablyat least 20 discrete particles per liter, more preferably at least 50discrete particles per liter and even more preferably at least 100discrete particles per liter.

The term polyisobutylene particles denote discrete particles of any formand consistency, which in a preferred embodiment have a particle size ofbetween 0.05 mm and 25 mm, more preferably between 0.1 and 20 mm.

In one embodiment the weight average particle size of the rubberparticles is from 0.3 to 10.0 mm.

It is apparent to those skilled in the art, that the polyisobutyleneparticles formed according to the invention may still contain organicdiluent and/or residual monomers and further may contain waterencapsulated within the polyisobutylene particle. In one embodiment thepolyisobutylene particles contain 90 wt.-% or more of thepolyisobutylene calculated on the sum of organic diluent, isobutyleneand polyisobutylene, preferably 93 wt.-% or more, more preferably 94wt.-% or more and even more preferably 96 wt.-% or more.

As mentioned above polyisobutylene particles are often referred to ascrumbs in the literature. Typically the polyisobutylene particles orcrumbs have non-uniform shape and/or geometry.

The term aqueous medium denotes a medium comprising 80 wt.-% or more ofwater, preferably 90 wt.-% or more 80 wt.-% and even more preferably 95wt.-% or more of water and yet even more preferably 99 wt.-% or more.

The remainder to 100 wt.-% includes the LCST compounds and may furtherinclude compounds selected from the group of

-   -   non-LCST compounds as defined above    -   compounds and salts which are neither an LCST compound nor a        non-LCST compound as defined above    -   organic diluents to the extent dissolvable in the aqueous medium    -   where an extended shelf life of the product is desired:        antioxidants and/or stabilizers.

In one embodiment the aqueous medium comprises of from 1 to 2,000 ppm ofantioxidants, preferably of from 50 to 1,000 ppm more preferably of from80 to 500 ppm calculated with respect to the amount of polyisobutylenepresent in the organic medium.

Where desired to obtain very high purity products the water employed toprepare the aqueous medium is demineralized by standard procedure suchas ion-exchange, membrane filtration techniques such as reverse osmosisand the like.

Typically application of water having a degree of 8.0 german degrees ofhardness (□dH) hardness or less, preferably 6.0 □dH or less, morepreferably 3.75 □dH or less and even more preferably 3.00 □dH or less issufficient.

In one embodiment the water is mixed with the at least one LCSTcompounds to obtain a concentrate which is depending on the temperatureeither a slurry or a solution having a LCST-compound concentration offrom 0.1 to 2 wt.-%, preferably 0.5 to 1 wt.-%. This concentrate is thenmetered into and diluted with more water in the vessel in which step A)is performed to the desired concentration.

Preferably the concentrate is a solution and metered into the vesselhaving a temperature of from 0 to 35□ C, preferably 10 to 30□ C.

If not mentioned otherwise, ppm refer to weight.-ppm.

The aqueous medium may further contain antioxidants and stabilizers:

Antioxidants and stabilizers include 2,6-di-tert.-butyl-4-methyl-phenol(BHT) andpentaerythrol-tetrakis-[3-(3,5-di-tert.-butyl-4-hydroxyphenyl)-propanoicacid (also known as Irganox□ 1010), octadecyl3,5-di(tert)-butyl-4-hydroxyhydrocinnamate (also known as Irganox□1076), tert-butyl-4-hydroxy anisole (BHA),2-(1,1-dimethyl)-1,4-benzenediol (TBHQ),tris(2,4,-di-tert-butylphenyl)phosphate (Irgafos□ 168),dioctyldiphenylamine (Stalite□ S), butylated products of p-cresol anddicyclopentadiene (Wingstay) as well as other phenolic antioxidants andhindered amine light stabilizers.

Suitable antioxidants generally include 2,4,6-tri-tert-butylphenol,2,4,6 tri-isobutylphenol, 2-tert-butyl-4,6-dimethylphenol,2,4-dibutyl-6-ethylphenol, 2,4-dimethyl-6-tert-butylphenol,2,6-di-tert-butylhydroyxytoluol (BHT), 2,6-di-tert-butyl-4-ethylphenol,2,6-di-tert-butyl-4-n-butylphenol, 2,6-di-tert-butyl-4-iso-butylphenol,2,6-dicyclopentyl-4-methylphenol, 4-tert-butyl-2,6-dimethylphenol,4-tert-butyl-2,6-dicyclopentylphenol,4-tert-butyl-2,6-diisopropylphenol, 4,6-di-tert-butyl-2-methylphenol,6-tert-butyl-2,4-dimethylphenol, 2,6-di-tert-butyl-3-methylphenol,4-hydroxymethyl-2,6-di-tert-butylphenol,2,6-di-tert-butyl-4-phenylphenol und 2,6-dioctadecyl-4-methylphenol,2,2□-ethylidene-bis[4,6-di-tert.-butylphenol],2,2□-ethylidene-bis[6-tert.-butyl-4-isobutylphenol],2,2□-isobutylidene-bis[4,6-dimethyl-phenol],2,2□-methylene-bis[4,6-di-tert.-butylphenol],2,2□-methylene-bis[4-methyl-6-(α-methylcyclohexyl)phenol],2,2□-methylene-bis[4-methyl-6-cyclohexylphenol],2,2□-methylene-bis[4-methyl-6-nonylphenol],2,2□-methylene-bis[6-(α,α□-dimethylbenzyl)-4-nonylphenol],2,2□-methylene-bis[6-(α-methylbenzyl)-4-nonylphenol],2,2□-methylene-bis[6-cyclohexyl-4-methylphenol],2,2□-methylene-bis[6-tert.-butyl-4-ethylphenol],2,2□-methylene-bis[6-tert.-butyl-4-methylphenol],4,4□-butylidene-bis[2-tert.-butyl-5-methylphenol],4,4□-methylene-bis[2,6-di-tert.-butylphenol],4,4□-methylene-bis[6-tert.-butyl-2-methylphenol],4,4□-isopropylidene-diphenol, 4,4′-decylidene-bisphenol,4,4′-dodecylidene-bisphenol, 4,4□-(1-methyloctylidene)bisphenol,4,4□-cyclohexylidene-bis(2-methylphenol), 4,4□-cyclohexylidenebisphenol,andpentaerythrol-tetrakis-[3-(3,5-di-tert.-butyl-4-hydroxyphenyl)-propanoicacid (also known as Irganox□ 1010).

In one embodiment the viscosity averaged molecular weight (M_(v)) of thepolyisobutylene is in the range of from 100 to 3,000 kg/mol, preferablyin the range of from 250 to 3,000 kg/mol.

In another embodiment the viscosity averaged molecular weight (M_(v)) ofthe polyisobutylene is in the range of from 100 to 2,000 kg/mol,preferably in the range of from 200 to 2,000 kg/mol, more preferably inthe range of from 350 to 1,800 kg/mol, even more preferably in the rangeof from 400 to 1500 kg/mol and yet even more preferably of from 700 to1300 kg/mol.

In yet another embodiment the viscosity averaged molecular weight(M_(v)) of the polyisobutylene is in the range of from 2,001 to 3,000kg/mol.

In yet another embodiment the viscosity averaged molecular weight(M_(v)) of the polyisobutylene is in the range of from 3,001 to 10,000kg/mol.

In one embodiment the polydispersity of the polyisobutylenes accordingto the invention is in the range of 3.0 to 5.5 as measured by the ratioof weight average molecular weight to number average molecular weight asdetermined by gel permeation chromatography.

The polyisobutylene for example and typically has a Mooney viscosity ofat least 10 (ML 1+8 at 125□ C, ASTM D 1646), preferably of from 10 to80, more preferably of from 20 to 80 and even more preferably of from 25to 60 (ML 1+8 at 125□ C, ASTM D 1646).

Monomers

In one embodiment the organic medium employed in step A) is obtained bya process comprising at least the steps of:

-   a) providing a reaction medium comprising an organic diluent, and    isobutylene-   b) polymerizing the isobutylene within the reaction medium in the    presence of an initiator system or catalyst to form an organic    medium comprising the polyisobutylene, the organic diluent and    optionally residual monomers

The isobutylene may be present in the reaction medium in an amount offrom 0.01 wt.-% to 80 wt.-%, preferably of from 0.1 wt.-% to 65 wt.-%,more preferably of from 10.0 wt.-% to 65.0 wt.-% and even morepreferably of from 25.0 wt.-% to 65.0 wt.-% or, in another embodiment10.0 to 20.0 wt.-%.

In one embodiment the isobutylene is purified before use in step a), inparticular when they are recycled from step d). Purification ofisobutylene may be carried out by passing through adsorbent columnscomprising suitable molecular sieves or alumina based adsorbentmaterials. In order to minimize interference with the polymerizationreaction, the total concentration of water and substances such asalcohols and other organic oxygenates that act as poisons to thereaction are preferably reduced to less than around 100 parts permillion on a weight basis.

Organic Diluents

The term organic diluent encompasses diluting or dissolving organicchemicals which are liquid under reactions conditions. Any suitableorganic diluent may be used which does not or not to any appreciableextent react with monomers or components of the initiator system.

However, those skilled in the art are aware that interactions betweenthe diluent and monomers or components of the initiator system or thecatalyst may occur.

Additionally, the term organic diluent includes mixtures of at least twodiluents.

Examples of organic diluents include hydrochlorocarbon(s) such as methylchloride, methylene chloride or ethyl chloride.

Further examples of organic diluents include hydrofluorocarbonsrepresented by the formula: C_(x)H_(y)F_(z) wherein x is an integer from1 to 40, alternatively from 1 to 30, alternatively from 1 to 20,alternatively from 1 to 10, alternatively from 1 to 6, alternativelyfrom 2 to 20 alternatively from 3 to 10, alternatively from 3 to 6, mostpreferably from 1 to 3, wherein y and z are integers and at least one.

In one embodiment the hydrofluorocarbon(s) is/are selected from thegroup consisting of saturated hydrofluorocarbons such as fluoromethane;difluoromethane; trifluoromethane; fluoroethane; 1,1-difluoroethane;1,2-difluoroethane; 1,1,1-trifluoroethane; 1,1-,2-trifluoroethane;1,1,2,2-tetrafluoroethane; 1,1,1,2,2-pentafluoroethane; 1-fluoropropane;2-fluoropropane; 1,1-difluoropropane; 1,2-difluoropropane;1,3-difluoropropane; 2,2-difluoropropane; 1,1,1-trifluoropropane;1,1,2-trifluoropropane; 1,1,3-trifluoropropane; 1,2,2-trifluoropropane;1,2,3-trifluoropropane; 1,1,1,2-tetrafluoropropane;1,1,1,3-tetrafluoropropane; 1,1,2,2-tetrafluoropropane;1,1,2,3-tetrafluoropropane; 1,1,3,3-tetrafluoropropane;1,2,2,3-tetrafluoropropane; 1,1,1,2,2-pentafluoropropane;1,1,1,2,3-pentafluoropropane; 1,1,1,3,3-pentafluoropropane;1,1,2,2,3-pentafluoropropane; 1,1,2,3,3-pentafluoropropane;1,1,1,2,2,3-hexafluoropropane; 1,1,1,2,3,3-hexafluoropropane;1,1,1,3,3,3-hexafluoropropane; 1,1,1,2,2,3,3-heptafluoropropane;1,1,1,2,3,3,3-heptafluoropropane; 1-fluorobutane; 2-fluorobutane;1,1-difluorobutane; 1,2-difluorobutane; 1,3-difluorobutane;1,4-difluorobutane; 2,2-difluorobutane; 2,3-difluorobutane;1,1,1-trifluorobutane; 1,1,2-trifluorobutane; 1,1,3-trifluorobutane;1,1,4-trifluorobutane; 1,2,2-trifluorobutane; 1,2,3-trifluorobutane;1,3,3-trifluorobutane; 2,2,3-trifluorobutane; 1,1,1,2-tetrafluorobutane;1,1,1,3-tetrafluorobutane; 1,1,1,4-tetrafluorobutane;1,1,2,2-tetrafluorobutane; 1,1,2,3-tetrafluorobutane;1,1,2,4-tetrafluorobutane; 1,1,3,3-tetrafluorobutane;1,1,3,4-tetrafluorobutane; 1,1,4,4-tetrafluorobutane;1,2,2,3-tetrafluorobutane; 1,2,2,4-tetrafluorobutane;1,2,3,3-tetrafluorobutane; 1,2,3,4-tetrafluorobutane;2,2,3,3-tetrafluorobutane; 1,1,1,2,2-pentafluorobutane;1,1,1,2,3-pentafluorobutane; 1,1,1,2,4-pentafluorobutane;1,1,1,3,3-pentafluorobutane; 1,1,1,3,4-pentafluorobutane;1,1,1,4,4-pentafluorobutane; 1,1,2,2,3-pentafluorobutane;1,1,2,2,4-pentafluorobutane; 1,1,2,3,3-pentafluorobutane;1,1,2,4,4-pentafluorobutane; 1,1,3,3,4-pentafluorobutane;1,2,2,3,3-pentafluorobutane; 1,2,2,3,4-pentafluorobutane;1,1,1,2,2,3-hexafluorobutane; 1,1,1,2,2,4-hexafluorobutane;1,1,1,2,3,3-hexafluorobutane, 1,1,1,2,3,4-hexafluorobutane;1,1,1,2,4,4-hexafluorobutane; 1,1,1,3,3,4-hexafluorobutane;1,1,1,3,4,4-hexafluorobutane; 1,1,1,4,4,4-hexafluorobutane;1,1,2,2,3,3-hexafluorobutane; 1,1,2,2,3,4-hexafluorobutane;1,1,2,2,4,4-hexafluorobutane; 1,1,2,3,3,4-hexafluorobutane;1,1,2,3,4,4-hexafluorobutane; 1,2,2,3,3,4-hexafluorobutane;1,1,1,2,2,3,3-heptafluorobutane; 1,1,1,2,2,4,4-heptafluorobutane;1,1,1,2,2,3,4-heptafluorobutane; 1,1,1,2,3,3,4-heptafluorobutane;1,1,1,2,3,4,4-heptafluorobutane; 1,1,1,2,4,4,4-heptafluorobutane;1,1,1,3,3,4,4-heptafluorobutane; 1,1,1,2,2,3,3,4-octafluorobutane;1,1,1,2,2,3,4,4-octafluorobutane; 1,1,1,2,3,3,4,4-octafluorobutane;1,1,1,2,2,4,4,4-octafluorobutane; 1,1,1,2,3,4,4,4-octafluorobutane;1,1,1,2,2,3,3,4,4-nonafluorobutane; 1,1,1,2,2,3,4,4,4-nonafluorobutane;1-fluoro-2-methylpropane; 1,1-difluoro-2-methylpropane;1,3-difluoro-2-methylpropane; 1,1,1-trifluoro-2-methylpropane;1,1,3-trifluoro-2-methylpropane; 1,3-difluoro-2-(fluoromethyl)propane;1,1,1,3-tetrafluoro-2-methylpropane;1,1,3,3-tetrafluoro-2-methylpropane;1,1,3-trifluoro-2-(fluoromethyl)propane;1,1,1,3,3-pentafluoro-2-methylpropane;1,1,3,3-tetrafluoro-2-(fluoromethyl)propane;1,1,1,3-tetrafluoro-2-(fluoromethyl)propane; fluorocyclobutane;1,1-difluorocyclobutane; 1,2-difluorocyclobutane;1,3-difluorocyclobutane; 1,1,2-trifluorocyclobutane;1,1,3-trifluorocyclobutane; 1,2,3-trifluorocyclobutane;1,1,2,2-tetrafluorocyclobutane; 1,1,3,3-tetrafluorocyclobutane;1,1,2,2,3-pentafluorocyclobutane; 1,1,2,3,3-pentafluorocyclobutane;1,1,2,2,3,3-hexafluorocyclobutane; 1,1,2,2,3,4-hexafluorocyclobutane;1,1,2,3,3,4-hexafluorocyclobutane; 1,1,2,2,3,3,4-heptafluorocyclobutane;

Particularly preferred HFC's include difluoromethane, trifluoromethane,1,1-difluoroethane, 1,1,1-trifluoroethane, fluoromethane, and1,1,1,2-tetrafluoroethane.

In one further embodiment the hydrofluorocarbon(s) is/are selected fromthe group consisting of unsaturated hydrofluorocarbons such as vinylfluoride; 1,2-difluoroethene; 1,1,2-trifluoroethene; 1-fluoropropene,1,1-difluoropropene; 1,2-difluoropropene; 1,3-difluoropropene;2,3-difluoropropene; 3,3-difluoropropene; 1,1,2-trifluoropropene;1,1,3-trifluoropropene; 1,2,3-trifluoropropene; 1,3,3-trifluoropropene;2,3,3-trifluoropropene; 3,3,3-trifluoropropene;2,3,3,3-tetrafluoro-1-propene; 1-fluoro-1-butene; 2-fluoro-1-butene;3-fluoro-1-butene; 4-fluoro-1-butene; 1,1-difluoro-1-butene;1,2-difluoro-1-butene; 1,3-difluoropropene; 1,4-difluoro-1-butene;2,3-difluoro-1-butene; 2,4-difluoro-1-butene; 3,3-difluoro-1-butene;3,4-difluoro-1-butene; 4,4-difluoro-1-butene; 1,1,2-trifluoro-1-butene;1,1,3-trifluoro-1-butene; 1,1,4-trifluoro-1-butene;1,2,3-trifluoro-1-butene; 1,2,4-trifluoro-1-butene;1,3,3-trifluoro-1-butene; 1,3,4-trifluoro-1-butene;1,4,4-trifluoro-1-butene; 2,3,3-trifluoro-1-butene;2,3,4-trifluoro-1-butene; 2,4,4-trifluoro-1-butene;3,3,4-trifluoro-1-butene; 3,4,4-trifluoro-1-butene;4,4,4-trifluoro-1-butene; 1,1,2,3-tetrafluoro-1-butene;1,1,2,4-tetrafluoro-1-butene; 1,1,3,3-tetrafluoro-1-butene;1,1,3,4-tetrafluoro-1-butene; 1,1,4,4-tetrafluoro-1-butene;1,2,3,3-tetrafluoro-1-butene; 1,2,3,4-tetrafluoro-1-butene;1,2,4,4-tetrafluoro-1-butene; 1,3,3,4-tetrafluoro-1-butene;1,3,4,4-tetrafluoro-1-butene; 1,4,4,4-tetrafluoro-1-butene;2,3,3,4-tetrafluoro-1-butene; 2,3,4,4-tetrafluoro-1-butene;2,4,4,4-tetrafluoro-1-butene; 3,3,4,4-tetrafluoro-1-butene;3,4,4,4-tetrafluoro-1-butene; 1,1,2,3,3-pentafluoro-1-butene;1,1,2,3,4-pentafluoro-1-butene; 1,1,2,4,4-pentafluoro-1-butene;1,1,3,3,4-pentafluoro-1-butene; 1,1,3,4,4-pentafluoro-1-butene;1,1,4,4,4-pentafluoro-1-butene; 1,2,3,3,4-pentafluoro-1-butene;1,2,3,4,4-pentafluoro-1-butene; 1,2,4,4,4-pentafluoro-1-butene;2,3,3,4,4-pentafluoro-1-butene; 2,3,4,4,4-pentafluoro-1-butene;3,3,4,4,4-pentafluoro-1-butene; 1,1,2,3,3,4-hexafluoro-1-butene;1,1,2,3,4,4-hexafluoro-1-butene; 1,1,2,4,4,4-hexafluoro-1-butene;1,2,3,3,4,4-bexafluoro-1-butene; 1,2,3,4,4,4-hexafluoro-1-butene;2,3,3,4,4,4-hexafluoro-1-butene; 1,1,2,3,3,4,4-heptafluoro-1-butene;1,1,2,3,4,4,4-heptafluoro-1-butene; 1,1,3,3,4,4,4-heptafluoro-1-butene;1,2,3,3,4,4,4-heptafluoro-1-butene; 1-fluoro-2-butene;2-fluoro-2-butene; 1,1-difluoro-2-butene; 1,2-difluoro-2-butene;1,3-difluoro-2-butene; 1,4-difluoro-2-butene; 2,3-difluoro-2-butene;1,1,1-trifluoro-2-butene; 1,1,2-trifluoro-2-butene;1,1,3-trifluoro-2-butene; 1,1,4-trifluoro-2-butene;1,2,3-trifluoro-2-butene; 1,2,4-trifluoro-2-butene;1,1,1,2-tetrafluoro-2-butene; 1,1,1,3-tetrafluoro-2-butene;1,1,1,4-tetrafluoro-2-butene; 1,1,2,3-tetrafluoro-2-butene;1,1,2,4-tetrafluoro-2-butene; 1,2,3,4-tetrafluoro-2-butene;1,1,1,2,3-pentafluoro-2-butene; 1,1,1,2,4-pentafluoro-2-butene;1,1,1,3,4-pentafluoro-2-butene; 1,1,1,4,4-pentafluoro-2-butene;1,1,2,3,4-pentafluoro-2-butene; 1,1,2,4,4-pentafluoro-2-butene;1,1,1,2,3,4-hexafluoro-2-butene; 1,1,1,2,4,4-hexafluoro-2-butene;1,1,1,3,4,4-hexafluoro-2-butene; 1,1,1,4,4,4-hexafluoro-2-butene;1,1,2,3,4,4-hexafluoro-2-butene; 1,1,1,2,3,4,4-heptafluoro-2-butene;1,1,1,2,4,4,4-heptafluoro-2-butene; and mixtures thereof.

Further examples of organic diluents include hydrochlorofluorocarbons.

Further examples of organic diluents include hydrocarbons, preferablyalkanes which in a further preferred embodiment are those selected fromthe group consisting of propane, isobutane, pentane, methycyclopentane,isohexane, 2-methylpentane, 3-methylpentane, 2-methylbutane,2,2-dimethylbutane, 2,3-dimethylbutane, 2-methylhexane, 3-methylhexane,3-ethylpentane, 2,2-dimethylpentane, 2,3-dimethylpentane,2,4-dimethylpentane, 3,3-dimethyl pentane, 2-methylheptane,3-ethylhexane, 2,5-dimethylhexane, 2,2,4,-trimethylpentane, octane,heptane, butane, ethane, methane, nonane, decane, dodecane, undecane,hexane, methyl cyclohexane, cyclopropane, cyclobutane, cyclopentane,methylcyclopentane, 1,1-dimethylcycopentane,cis-1,2-dimethylcyclopentane, trans-1,2-dimethylcyclopentane,trans-1,3-dimethyl-cyclopentane, ethylcyclopentane, cyclohexane,methylcyclohexane.

Further examples of hydrocarbon diluents include benzene, toluene,xylene, ortho-xylene, para-xylene and meta-xylene.

Suitable organic diluents further include mixtures of at least twocompounds selected from the groups of hydrochlorocarbons,hydrofluorocarbons, hydrochlorofluorocarbons and hydrocarbons. Specificcombinations include mixtures of hydrochlorocarbons andhydrofluorocarbons such as mixtures of methyl chloride and1,1,1,2-tetrafluoroethane in particular those of 40 to 60 vol.-% methylchloride and 40 to 60 vol.-% 1,1,1,2-tetrafluoroethane whereby theaforementioned two diluents add up to 90 to 100 vol.-%, preferably to 95to 100 vol. % of the total diluent, whereby the potential remainder to100 vol. % includes other halogenated hydrocarbons; or mixtures ofmethyl chloride and at least one alkane or mixtures of alkanes such asmixtures comprising at least 90 wt.-%, preferably 95 wt.-% of alkaneshaving a boiling point at a pressure of 1013 hPa of −5□ C to 100□ C orin another embodiment 35□ C to 85□ C. In another embodiment least 99.9wt.-%, preferably 100 wt.-% of the alkanes have a boiling point at apressure of 1013 hPa of 100□ C or less, preferably in the range of from35 to 100□ C, more preferably 90□ C or less, even more preferably in therange of from 35 to 90□ C.

Depending on the nature of the polymerization intended for step b) theorganic diluent is selected to allow a slurry polymerization or asolution polymerization

Initiator System

In step b) the isobutylene within the reaction medium is polymerized inthe presence of an initiator system to form a medium comprising thepolyisobutylene, the organic diluent and optionally residualisobutylene.

Initiator systems in particular for polyisobutylenes obtained bycationic polymerizations typically comprise at least one Lewis acid andan initiator.

Lewis Acids

Suitable Lewis acids include compounds represented by formula MX₃, whereM is a group 13 element and X is a halogen. Examples for such compoundsinclude aluminum trichloride, aluminum tribromide, boron trichloride,boron tribromide, gallium trichloride and indium trifluoride, wherebyaluminum trichloride is preferred.

Further suitable Lewis acids include compounds represented by formulaMR_((m))X_((3−m)), where M is a group 13 element, X is a halogen, R is amonovalent hydrocarbon radical selected from the group consisting ofC₁-C₁₂ alkyl, C₆-C₁₀ aryl, C₇-C₁₄ arylalkyl and C₇-C₁₄ alkylarylradicals; and m is one or two. X may also be an azide, an isocyanate, athiocyanate, an isothiocyanate or a cyanide.

Examples for such compounds include methyl aluminum dibromide, methylaluminum dichloride, ethyl aluminum dibromide, ethyl aluminumdichloride, butyl aluminum dibromide, butyl aluminum dichloride,dimethyl aluminum bromide, dimethyl aluminum chloride, diethyl aluminumbromide, diethyl aluminum chloride, dibutyl aluminum bromide, dibutylaluminum chloride, methyl aluminum sesquibromide, methyl aluminumsesquichloride, ethyl aluminum sesquibromide, ethyl aluminumsesquichloride and any mixture thereof. Preferred are diethyl aluminumchloride (Et₂AlCl or DEAC), ethyl aluminum sesquichloride(Et_(1.5)AlCl_(1.5) or EASC), ethyl aluminum dichloride (EtAlCl₂ orEADC), diethyl aluminum bromide (Et₂AlBr or DEAB), ethyl aluminumsesquibromide (Et_(1.5)AlBr_(1.5) or EASB) and ethyl aluminum dibromide(EtAlBr₂ or EADB) and any mixture thereof.

Further suitable Lewis acids include compounds represented by formulaM(RO)_(n)R′_(m)X_((3−(m+n))); wherein M is a Group 13 metal; wherein ROis a monovalent hydrocarboxy radical selected from the group consistingof C₁-C₃₀ alkoxy, C₇-C₃₀ aryloxy, C₇-C₃₀ arylalkoxy, C₇-C₃₀alkylaryloxy; R′ is a monovalent hydrocarbon radical selected from thegroup consisting of C₁-C₁₂ alkyl, C₆-C₁₀ aryl, C₇-C₁₄ arylalkyl andC₇-C₁₄ alkylaryl radicals as defined above; n is a number from 0 to 3and m is an number from 0 to 3 such that the sum of n and m is not morethan 3;

X is a halogen independently selected from the group consisting offluorine, chlorine, bromine, and iodine, preferably chlorine. X may alsobe an azide, an isocyanate, a thiocyanate, an isothiocyanate or acyanide.

For the purposes of this invention, one skilled in the art wouldrecognize that the terms alkoxy and aryloxy are structural equivalentsto alkoxides and phenoxides respectively. The term “arylalkoxy” refersto a radical comprising both aliphatic and aromatic structures, theradical being at an alkoxy position. The term “alkylaryl” refers to aradical comprising both aliphatic and aromatic structures, the radicalbeing at an aryloxy position.

Non-limiting examples of these Lewis acids include methoxyaluminumdichloride, ethoxyaluminum dichloride, 2,6-di-tert-butylphenoxyaluminumdichloride, methoxy methylaluminum chloride, 2,6-di-tert-butylphenoxymethylaluminum chloride, isopropoxygallium dichloride and phenoxymethylindium fluoride.

Further suitable Lewis acids include compounds represented by formulaM(RC═OO)_(n)R′_(m)X_((3−(m+n))) wherein M is a Group 13 metal; whereinRC═OO is a monovalent hydrocarbacyl radical selected from the groupselected from the group consisting of C₁-C₃₀ alkacyloxy, C₇-C₃₀arylacyloxy, C₇-C₃₀ arylalkylacyloxy, C₇-C₃₀ alkylarylacyloxy radicals;R′ is a monovalent hydrocarbon radical selected from the groupconsisting of C₁-C₁₂ alkyl, C₆-C₁₀ aryl, C₇-C₁₄ arylalkyl and C₇-C₁₄alkylaryl radicals as defined above; n is a number from 0 to 3 and m isa number from 0 to 3 such that the sum of n and m is not more than 3; Xis a halogen independently selected from the group consisting offluorine, chlorine, bromine, and iodine, preferably chlorine. X may alsobe an azide, an isocyanate, a thiocyanate, an isothiocyanate or acyanide.

The term “arylalkylacyloxy” refers to a radical comprising bothaliphatic and aromatic structures, the radical being at an alkyacyloxyposition. The term “alkylarylacyloxy” refers to a radical comprisingboth aliphatic and aromatic structures, the radical being at anarylacyloxy position. Non-limiting examples of these Lewis acids includeacetoxyaluminum dichloride, benzoyloxyaluminum dibromide,benzoyloxygallium difluoride, methyl acetoxyaluminum chloride, andisopropoyloxyindium trichloride.

Further suitable Lewis acids include compounds based on metals of Group4, 5, 14 and 15 of the Periodic Table of the Elements, includingtitanium, zirconium, tin, vanadium, arsenic, antimony, and bismuth.

One skilled in the art will recognize, however, that some elements arebetter suited in the practice of the invention. The Group 4, 5 and 14Lewis acids have the general formula MX₄; wherein M is Group 4, 5, or 14metal; and X is a halogen independently selected from the groupconsisting of fluorine, chlorine, bromine, and iodine, preferablychlorine. X may also be a azide, an isocyanate, a thiocyanate, anisothiocyanate or a cyanide. Non-limiting examples include titaniumtetrachloride, titanium tetrabromide, vanadium tetrachloride, tintetrachloride and zirconium tetrachloride. The Group 4, 5, or 14 Lewisacids may also contain more than one type of halogen. Non-limitingexamples include titanium bromide trichloride, titanium dibromidedichloride, vanadium bromide trichloride, and tin chloride trifluoride.

Group 4, 5 and 14 Lewis acids useful in this invention may also have thegeneral formula MR_(n)X_((4−n);) wherein M is Group 4, 5, or 14 metal;wherein R is a monovalent hydrocarbon radical selected from the groupconsisting of C₁-C₁₂ alkyl, C₆-C₁₀ aryl, C₇-C₁₄ arylalkyl and C₇-C₁₄alkylaryl radicals; n is an integer from 0 to 4; X is a halogenindependently selected from the group consisting of fluorine, chlorine,bromine, and iodine, preferably chlorine. X may also be an azide, anisocyanate, a thiocyanate, an isothiocyanate or a cyanide.

The term “arylalkyl” refers to a radical comprising both aliphatic andaromatic structures, the radical being at an alkyl position.

The term “alkylaryl” refers to a radical comprising both aliphatic andaromatic structures, the radical being at an aryl position.

Non-limiting examples of these Lewis acids include benzyltitaniumtrichloride, dibenzyltitanium dichloride, benzylzirconium trichloride,dibenzylzirconium dibromide, methyltitanium trichloride,dimethyltitanium difluoride, dimethyltin dichloride and phenylvanadiumtrichloride.

Group 4, 5 and 14 Lewis acids useful in this invention may also have thegeneral formula M(RO)_(n)R′_(m)X_(4−(m+n)); wherein M is Group 4, 5, or14 metal, wherein RO is a monovalent hydrocarboxy radical selected fromthe group consisting of C₁-C₃₀ alkoxy, C₇-C₃₀ aryloxy, C₇-C₃₀arylalkoxy, C₇-C₃₀ alkylaryloxy radicals; R′ is a monovalent hydrocarbonradical selected from the group consisting of C₁-C₁₂alkyl, C₆-C₁₀ aryl,C₇-C₁₄ arylalkyl and C₇-C₁₄ alkylaryl radicals as defined above, R is amonovalent hydrocarbon radical selected from the group consisting ofC₁-C₁₂ alkyl, C₆-C₁₀ aryl, C₇-C₁₄ arylalkyl and C₇-C₁₄ alkylarylradicals as defined above; n is an integer from 0 to 4 and m is aninteger from 0 to 4 such that the sum of n and m is not more than 4; Xis selected from the group consisting of fluorine, chlorine, bromine,and iodine, preferably chlorine. X may also be an azide, an isocyanate,a thiocyanate, an isothiocyanate or a cyanide.

For the purposes of this invention, one skilled in the art wouldrecognize that the terms alkoxy and aryloxy are structural equivalentsto alkoxides and phenoxides respectively. The term “arylalkoxy” refersto a radical comprising both aliphatic and aromatic structures, theradical being at an alkoxy position.

The term “alkylaryl” refers to a radical comprising both aliphatic andaromatic structures, the radical being at an aryloxy position.Non-limiting examples of these Lewis acids include methoxytitaniumtrichloride, n-butoxytitanium trichloride, di(isopropoxy)titaniumdichloride, phenoxytitanium tribromide, phenylmethoxyzirconiumtrifluoride, methyl methoxytitanium dichloride, methyl methoxytindichloride and benzyl isopropoxyvanadium dichloride.

Group 4, 5 and 14 Lewis acids useful in this invention may also have thegeneral formula M(RC═OO)_(n)R′_(m)X_(4−(m+n);) wherein M is Group 4, 5,or 14 metal; wherein RC═OO is a monovalent hydrocarbacyl radicalselected from the group consisting of C₁-C₃₀ alkacyloxy, C₇-C₃₀arylacyloxy, C₇-C₃₀ arylalkylacyloxy, C₇-C₃₀ alkylarylacyloxy radicals;R′ is a monovalent hydrocarbon radical selected from the groupconsisting of C₁-C₁₂ alkyl, C₆-C₁₀ aryl, C₇-C₁₄ arylalkyl and C₇-C₁₄alkylaryl radicals as defined above; n is an integer from 0 to 4 and mis an integer from 0 to 4 such that the sum of n and m is not more than4; X is a halogen independently selected from the group consisting offluorine, chlorine, bromine, and iodine, preferably chlorine. X may alsobe an azide, an isocyanate, a thiocyanate, an isothiocyanate or acyanide.

The term “arylalkylacyloxy” refers to a radical comprising bothaliphatic and aromatic structures, the radical being at an alkylacyloxyposition.

The term “alkylarylacyloxy” refers to a radical comprising bothaliphatic and aromatic structures, the radical being at an arylacyloxyposition. Non-limiting examples of these Lewis acids includeacetoxytitanium trichloride, benzoylzirconium tribromide,benzoyloxytitanium trifluoride, isopropoyloxytin trichloride, methylacetoxytitanium dichloride and benzyl benzoyloxyvanadium chloride.

Group 5 Lewis acids useful in this invention may also have the generalformula MOX₃; wherein M is a Group 5 metal and wherein X is a halogenindependently selected from the group consisting of fluorine, chlorine,bromine, and iodine, preferably chlorine. A non-limiting example isvanadium oxytrichloride. The Group 15 Lewis acids have the generalformula MX_(y), wherein M is a Group 15 metal and X is a halogenindependently selected from the group consisting of fluorine, chlorine,bromine, and iodine, preferably chlorine and y is 3, 4 or 5. X may alsobe an azide, an isocyanate, a thiocyanate, an isothiocyanate or acyanide. Non-limiting examples include antimony hexachloride, antimonyhexafluoride, and arsenic pentafluoride. The Group 15 Lewis acids mayalso contain more than one type of halogen. Non-limiting examplesinclude antimony chloride pentafluoride, arsenic trifluoride, bismuthtrichloride and arsenic fluoride tetrachloride.

Group 15 Lewis acids useful in this invention may also have the generalformula MR_(n)X_(y−n;) wherein M is a Group 15 metal; wherein R is amonovalent hydrocarbon radical selected from the group consisting ofC₁-C₁₂ alkyl, C₆-C₁₀ aryl, C₇-C₁₄ arylalkyl and C₇-C₁₄ alkylarylradicals; and n is an integer from 0 to 4; y is 3, 4 or 5 such that n isless than y; X is a halogen independently selected from the groupconsisting of fluorine, chlorine, bromine, and iodine, preferablychlorine. X may also be a an azide, an isocyanate, a thiocyanate, anisothiocyanate or a cyanide. The term “arylalkyl” refers to a radicalcomprising both aliphatic and aromatic structures, the radical being atan alkyl position. The term “alkylaryl” refers to a radical comprisingboth aliphatic and aromatic structures, the radical being at an arylposition. Non-limiting examples of these Lewis acids includetetraphenylantimony chloride and triphenylantimony dichloride.

Group 15 Lewis acids useful in this invention may also have the generalformula M(RO)_(n)R′_(m)X_(y−(m+n);) wherein M is a Group 15 metal,wherein RO is a monovalent hydrocarboxy radical selected from the groupconsisting of C₁-C₃₀ alkoxy, C₇-C₃₀ aryloxy, C₇-C₃₀ arylalkoxy, C₇-C₃₀alkylaryloxy radicals; R′ is a monovalent hydrocarbon radical selectedfrom the group consisting of C₁-C₁₂ alkyl, C₆-C₁₀ aryl, C₇-C₁₄ arylalkyland C₇-C₁₄ alkylaryl radicals as defined above; n is an integer from 0to 4 and m is an integer from 0 to 4 and y is 3, 4 or 5 such that thesum of n and m is less than y; X is a halogen independently selectedfrom the group consisting of fluorine, chlorine, bromine, and iodine,preferably chlorine. X may also be an azide, an isocyanate, athiocyanate, an isothiocyanate or a cyanide. For the purposes of thisinvention, one skilled in the art would recognize that the terms alkoxyand aryloxy are structural equivalents to alkoxides and phenoxidesrespectively. The term “arylalkoxy” refers to a radical comprising bothaliphatic and aromatic structures, the radical being at an alkoxyposition. The term “alkylaryl” refers to a radical comprising bothaliphatic and aromatic structures, the radical being at an aryloxyposition. Non-limiting examples of these Lewis acids includetetrachloromethoxyantimony, dimethoxytrichloroantimony,dichloromethoxyarsine, chlorodimethoxyarsine, and difluoromethoxyarsine.Group 15 Lewis acids useful in this invention may also have the generalformula M(RC═OO)_(n)R′_(m)X_(y−(m+n)); wherein M is a Group 15 metal;wherein RC═OO is a monovalent hydrocarbacyloxy radical selected from thegroup consisting of C₁-C₃₀ alkacyloxy, C₇-C₃₀ arylacyloxy, C₇-C₃₀arylalkylacyloxy, C₇-C₃₀ alkylarylacyloxy radicals; R′ is a monovalenthydrocarbon radical selected from the group consisting of C₁-C₁₂ alkyl,C₆-C₁₀ aryl, C₇-C₁₄ arylalkyl and C₇-C₁₄ alkylaryl radicals as definedabove; n is an integer from 0 to 4 and m is an integer from 0 to 4 and yis 3, 4 or 5 such that the sum of n and m is less than y; X is a halogenindependently selected from the group consisting of fluorine, chlorine,bromine, and iodine, preferably chlorine. X may also be an azide, anisocyanate, a thiocyanate, an isothiocyanate or a cyanide. The term“arylalkylacyloxy” refers to a radical comprising both aliphatic andaromatic structures, the radical being at an alkyacyloxy position. Theterm “alkylarylacyloxy” refers to a radical comprising both aliphaticand aromatic structures, the radical being at an arylacyloxy position.Non-limiting examples of these Lewis acids includeacetatotetrachloroantimony, (benzoato) tetrachloroantimony, and bismuthacetate chloride.

Lewis acids such as methylaluminoxane (MAO) and specifically designedweakly coordinating Lewis acids such as B(C₆F₅)₃ are also suitable Lewisacids within the context of the invention.

Weakly coordinating Lewis acids are exhaustively disclosed in WO2004/067577A in sections [117] to [129] which are hereby incorporated byreference.

Initiators

Initiators useful in this invention are those initiators which arecapable of being complexed with the chosen Lewis acid to yield a complexwhich reacts with the monomers thereby forming a propagating polymerchain.

In a preferred embodiment the initiator comprises at least one compoundselected from the groups consisting of water, hydrogen halides,carboxylic acids, carboxylic acid halides, sulfonic acids, sulfonic acidhalides, alcohols, phenols, tertiary alkyl halides, tertiary aralkylhalides, tertiary alkyl esters, tertiary aralkyl esters, tertiary alkylethers, tertiary aralkyl ethers, alkyl halides, aryl halides, alkylarylhalides and arylalkylacid halides.

Preferred hydrogen halide initiators include hydrogen chloride, hydrogenbromide and hydrogen iodide. A particularly preferred hydrogen halide ishydrogen chloride.

Preferred carboxylic acids include both aliphatic and aromaticcarboxylic acids. Examples of carboxylic acids useful in this inventioninclude acetic acid, propanoic acid, butanoic acid; cinnamic acid,benzoic acid, 1-chloroacetic acid, dichloroacetic acid, trichloroaceticacid, trifluoroacetic acid, p-chlorobenzoic acid, and p-fluorobenzoicacid. Particularly preferred carboxylic acids include trichloroaceticacid, trifluoroacteic acid, and p-fluorobenzoic acid.

Carboxylic acid halides useful in this invention are similar instructure to carboxylic acids with the substitution of a halide for theOH of the acid. The halide may be fluoride, chloride, bromide, oriodide, with the chloride being preferred.

Carboxylic acid halides useful in this invention include acetylchloride, acetyl bromide, cinnamyl chloride, benzoyl chloride, benzoylbromide, trichloroacetyl chloride, trifluoroacetylchloride,trifluoroacetyl chloride and p-fluorobenzoylchloride. Particularlypreferred acid halides include acetyl chloride, acetyl bromide,trichloroacetyl chloride, trifluoroacetyl chloride and p-fluorobenzoylchloride.

Sulfonic acids useful as initiators in this invention include bothaliphatic and aromatic sulfonic acids. Examples of preferred sulfonicacids include methanesulfonic acid, trifluoromethanesulfonic acid,trichloromethanesulfonic acid and p-toluenesulfonic acid.

Sulfonic acid halides useful in this invention are similar in structureto sulfonic acids with the substitution of a halide for the OH of theparent acid. The halide may be fluoride, chloride, bromide or iodide,with the chloride being preferred. Preparation of the sulfonic acidhalides from the parent sulfonic acids are known in the prior art andone skilled in the art should be familiar with these procedures.Preferred sulfonic acid halides useful in this invention includemethanesulfonyl chloride, methanesulfonyl bromide,trichloromethanesulfonyl chloride, trifluoromethanesulfonyl chloride andp-toluenesulfonyl chloride.

Alcohols useful in this invention include methanol, ethanol, propanol,2-propanol, 2-methylpropan-2-ol, cyclohexanol, and benzyl alcohol.

Phenols useful in this invention include phenol; 2-methylphenol;2,6-dimethylphenol; p-chlorophenol; p-fluorophenol;2,3,4,5,6-pentafluorophenol; and 2-hydroxynaphthalene.

The initiator system may further comprise oxygen- or nitrogen-containingcompounds other than the aforementioned to further influence or enhancethe activity.

Such compounds include ethers, amines, N-heteroaromatic compounds,ketones, sulfones and sulfoxides as well as carboxylic acid esters andamides

Ethers include methyl ethyl ether, diethyl ether, di-n-propyl ether,tert.-butyl-methyl ether, di-n-butyl ether, tetrahydrofurane, dioxane,anisole or phenetole.

Amines include n-pentyl amine, N,N-diethyl methylamine, N,N-dimethylpropylamine, N-methyl butylamine, N,N-dimethyl butylamine, N-ethylbutylamine, hexylamine, N-methyl hexylamine, N-butyl propylamine, heptylamine, 2-amino heptane, 3-amino heptane, N,N-dipropyl ethyl amine,N,N-dimethyl hexylamine, octylamine, aniline, benzylamine, N-methylaniline, phenethylamine, N-ethyl aniline, 2,6-diethyl aniline,amphetamine, N-propyl aniline, phentermine, N-butyl aniline, N,N-diethylaniline, 2,6-diethyl aniline, diphenylamine, piperidine, N-methylpiperidine and triphenylamine.

N-heteroaromatic compounds include pyridine, 2-,3- or 4-methyl pyridine,dimethyl pyridine, ethylene pyridine and 3-methyl-2-phenyl pyridine.

Ketones include acetone, butanone, pentanone, hexanone, cyclohexanone,2,4-hexanedione, acetylacetone and acetonyl acetone.

Sulfones and sulfoxides include dimethyl sulfoxide, diethyl sulfoxideand sulfolane.

Carboxylic acid esters include methyl acetate, ethyl acetate, vinylacetate, propyl acetate, allyl acetate, benzyl acetate, methyl acrylate,ethyl acrylate, propyl acrylate, butyl acrylate, methyl methacrylate,ethyl methacrylate, propyl methacrylate, butyl methacrylate, dimethylmaleate, diethyl maleate, dipropyl maleate, methyl benzoate, ethylbenzoate, propyl benzoate, butyl benzoate, allyl benzoate, butylidenebenzoate, benzyl benzoate, phenylethyl benzoate, dimethyl phthalate,diethyl phthalate, dipropyl phthalate, dibutyl phthalate, dipentylphthalate, dihexyl phthalate, diheptyl phthalate and dioctyl phthalate.

Carboxylic acid amides include N,N-dimethyl formamide, N,N-dimethylacetamide, N,N-diethyl formamide and N,N-diethyl acetamide.

Preferred tertiary alkyl and aralkyl initiators include tertiarycompounds represented by the formula below: wherein X is a halogen,pseudohalogen, ether, or ester, or a mixture thereof, preferably ahalogen, preferably chloride and R₁, R₂ and R₃ are independently anylinear, cyclic or branched chain alkyls, aryls or arylalkyls, preferablycomprising 1 to 15 carbon atoms and more preferably 1 to 8 carbon atoms.n is the number of initiator sites and is a number greater than or equalto 1, preferably between 1 to 30, more preferably n is a number from 1to 6. The arylalkyls may be substituted or unsubstituted. For thepurposes of this invention and any claims thereto, arylalkyl is definedto mean a compound comprising both aromatic and aliphatic structures.Preferred examples of initiators include2-chloro-2,4,4-trimethylpentane; 2-bromo-2,4,4-trimethylpentane;2-chloro-2-methylpropane; 2-bromo-2-methylpropane;2-chloro-2,4,4,6,6-pentamethylheptane;2-bromo-2,4,4,6,6-pentamethylheptane; 1-chloro-1-methylethylbenzene;1-chloroadamantane; 1-chloroethylbenzene; 1,4-bis(1-chloro-1-methylethyl) benzene;5-tert-butyl-1,3-bis(1-chloro-1-methylethyl) benzene;2-acetoxy-2,4,4-trimethylpentane; 2-benzoyloxy-2,4,4-trimethylpentane;2-acetoxy-2-methylpropane; 2-benzoyloxy-2-methylpropane;2-acetoxy-2,4,4,6,6-pentamethylheptane;2-benzoyl-2,4,4,6,6-pentamethylheptane; 1-acetoxy-1-methylethylbenzene;1-aceotxyadamantane; 1-benzoyloxyethylbenzene;1,4-bis(1-acetoxy-1-methylethyl) benzene;5-ten-butyl-1,3-bis(1-acetoxy-1-methylethyl) benzene;2-methoxy-2,4,4-trimethylpentane; 2-isopropoxy-2,4,4-trimethylpentane;2-methoxy-2-methylpropane; 2-benzyloxy-2-methylpropane;2-methoxy-2,4,4,6,6-pentamethylheptane;2-isopropoxy-2,4,4,6,6-pentamethylheptane;1-methoxy-1-methylethylbenzene; 1-methoxyadamantane;1-methoxyethylbenzene; 1,4-bis(1-methoxy-1-methylethyl) benzene;5-tert-butyl-1,3-bis(1-methoxy-1-methylethyl) benzene and1,3,5-tris(1-chloro-1-methylethyl) benzene. Other suitable initiatorscan be found in U.S. Pat. No. 4,946,899. For the purposes of thisinvention and the claims thereto pseudohalogen is defined to be anycompound that is an azide, an isocyanate, a thiocyanate, anisothiocyanate or a cyanide.

Another preferred initiator is a polymeric halide, one of R₁, R₂ or R₃is an olefin polymer and the remaining R groups are defined as above.Preferred olefin polymers include polyisobutylene, polypropylene, andpolyvinylchloride. The polymeric initiator may have halogenated tertiarycarbon positioned at the chain end or along or within the backbone ofthe polymer. When the olefin polymer has multiple halogen atoms attertiary carbons, either pendant to or within the polymer backbone, theproduct may contain polymers which have a comb like structure and/orside chain branching depending on the number and placement of thehalogen atoms in the olefin polymer. Likewise, the use of a chain endtertiary polymer halide initiator provides a method for producing aproduct which may contain block polyisobutylenes.

Particularly preferred initiators may be any of those useful in cationicpolymerization of isobutylene polyisobutylenes including: water,hydrogen chloride, 2-chloro-2,4,4-trimethylpentane,2-chloro-2-methylpropane, 1-chloro-1-methylethylbenzene, and methanol.

Initiator systems useful in this invention may further comprisecompositions comprising a reactive cation and a weakly-coordinatinganion (“WCA□) as defined above.

A preferred mole ratio of Lewis acid to initiator is generally from 1:5to 100:1 preferably from or from 5:1 to 100:1, more preferably from 8:1to 20:1.

The initiator system including the lewis acid and the initiator ispreferably present in the reaction mixture in an amount of 0.002 to 5.0wt.-%, preferably of 0.1 to 0.5 wt.-%, based on the weight of themonomers employed.

In another embodiment, in particular where aluminum trichloride isemployed the wt.-ratio of monomers employed to lewis acid, in particularaluminum trichloride is within a range of 500 to 20000, preferably 1500to 10000.

In one embodiment at least one control agent for the initiator system isemployed. Control agent help to control activity and thus to adjust theproperties, in particular the molecular weight of the desired copolymer,see e.g. U.S. Pat. No. 2,580,490 and U.S. Pat. No. 2,856,394.

Suitable control agents comprise ethylene, mono- or di-substitutedC₃-C₂₀ monoalkenes, whereby substitution is meant to denote thealkyl-groups bound to the olefinic double bond. Preferred control agentsare monosubstituted C₃-C₂₀ monoalkenes (also called primary olefins),more preferred control agents are (C₃-C₂₀)-1-alkenes, such as 1-butene.The aforementioned control agents ethylene, mono- or di-substitutedC₃-C₂₀ monoalkenes are typically applied in an amount of from 0.01 to 20wt.-% calculated on the monomers employed in step a), preferably in anamount of from 0.2 to 15 wt.-% and more preferably in an amount of from1 to 15 wt.-%.

Another suitable control agent comprises diisobutylene(2,4,4-trimethyl-1-pentene). Diisobutylene may be used alternatively oradditionally to ethylene, mono- or di-substituted C₃-C₂₀ monoalkenes.Diisobutylene is typically applied in an amount of from 0.001 to 3 wt.-%calculated on the monomers employed in step a), preferably in an amountof from 0.01 to 2 wt.-% and more preferably in an amount of from 0.01 to1.5 wt.-%.

It is of course understood that greater or lesser amounts of initiatorare still within the scope of this invention.

In a particularly preferred initiator system, the Lewis acid is ethylaluminum sesquichloride, preferably generated by mixing equimolaramounts of diethyl aluminum chloride and ethyl aluminum dichloride,preferably in a diluent. The diluent is preferably the same one used toperform the polymerization reaction.

Where alkyl aluminum halides are employed water and/or alcohols,preferably water is used as proton source. In one embodiment the amountof water is in the range of 0.40 to 4.0 moles of water per mole ofaluminum of the alkyl aluminum halides, preferably in the range of 0.5to 2.5 moles of water per mole of aluminum of the alkyl aluminumhalides, most preferably 1 to 2 moles of water per mole of the aluminumalkyl halide.

Where aluminum halides, in particular aluminum trichloride are employedwater and/or alcohols, preferably water is used as proton source.

In one embodiment the amount of water is in the range of 0.05 to 2.0moles of water per mole of aluminum in the aluminum halides, preferablyin the range of 0.1 to 1.2 moles of water per mole of aluminum in thealuminum halides.

Polymerization Conditions

In one embodiment, the organic diluent and the isobutylene employed aresubstantially free of water. As used herein substantially free of wateris defined as less than 50 ppm based upon total weight of the reactionmedium, preferably less than 30 ppm, more preferably less than 20 ppm,even more preferably less than 10 ppm, yet even more preferably lessthan 5 ppm.

One skilled of the art is aware that the water content in the organicdiluent and the isobutylene needs to be low to ensure that the initiatorsystem is not affected by additional amounts of water which are notadded by purpose e.g. to serve as an initiator.

Steps a) and/or b) may be carried out in continuous or batch processes,whereby continuous processes are preferred.

In an embodiment of the invention the polymerization according to stepb) is effected using a polymerization reactor. Suitable reactors arethose known to the skilled in the art and include flow-throughpolymerization reactors, plug flow reactor, stirred tank reactors,moving belt or drum reactors, jet or nozzle reactors, tubular reactors,and autorefrigerated boiling-pool reactors. Specific suitable examplesare disclosed in WO 2011/000922 A and WO 2012/089823 A.

In one embodiment, the polymerization according to step b) is carriedout where the initiator system, the isobutylene and the organic diluentare present in a single phase. Preferably, the polymerization iscarried-out in a continuous polymerization process in which theinitiator system, monomer(s) and the organic diluent are present as asingle phase.

Depending on the choice of the organic diluent the polymerizationaccording to step b) is carried out either as slurry polymerization orsolution polymerization.

In slurry polymerization, the isobutylene, the initiator system are alltypically soluble in the diluent or diluent mixture, i.e., constitute asingle phase, while the polyisobutylene upon formation precipitates fromthe organic diluent. Desirably, reduced or no polymer “swelling” isexhibited as indicated by little or no Tg suppression of the polymerand/or little or no organic diluent mass uptake.

In solution polymerization, the monomers, the initiator system are alltypically soluble in the diluent or diluent mixture, i.e., constitute asingle phase as is the polyisobutylene formed during polymerization.

The solubilities of the desired polymers in the organic diluentsdescribed above as well as their swelling behaviour under reactionconditions is well known to those skilled in the art.

The advantages and disadvantages of solution versus slurrypolymerization are exhaustively discussed in the literature and thus arealso known to those skilled in the art.

In one embodiment step b) is carried out at a temperature in the rangeof −110□ C to 20□ C, preferably in the range of −100□ C to −50□ C andeven more preferably in the range of −100□ C to −70□ C.

In a preferred embodiment, the polymerization temperature is within 20□C above the freezing point of the organic diluent, preferably within 10□C above the freezing point of the organic diluent.

The reaction pressure in step b) is typically from 100 to 100,000 hP,preferably from 200 to 20,000 hPa, more preferably from 500 to 5,000hPa.

The polymerization according to step b) is typically carried out in amanner that the solids content of the slurry in step b) is preferably inthe range of from 1 to 45 wt.-%, more preferably 3 to 40 wt.-%, evenmore preferably 15 to 40 wt.-%.

As used herein the terms □solids content□ or □solids level□ refer toweight percent of the polyisobutylene obtained according to step b) i.e.in polymerization and present in the medium comprising thepolyisobutylene, the organic diluent and optionally residual monomersobtained according to step b).

In one embodiment the reaction time in step b) is from 2 min to 2 h,preferably from 10 min to 1 h and more preferably from 20 to 45 min.

The process may be carried out batchwise or continuously. Where acontinuous reaction is performed the reaction time given aboverepresents the average residence time.

In one embodiment the reaction is stopped by quenching agents forexample a 1 wt.-% sodium hydroxide solution in water, methanol orethanol.

In another embodiment the reaction is quenched by the contact with theaqueous medium in step A), which in one embodiment may have a pH valueof 5 to 10, preferably 6 to 9 and more preferably 7 to 9 measured at 20□C and 1013 hPa.

The pH-Adjustment where desired may be performed by addition of acids oralkaline compounds which preferably do not contain multivalent metalions. pH adjustment to higher pH values is e.g. effected by addition ofsodium or potassium hydroxide.

In particular for solution polymerizations the conversion is typicallystopped after a monomer consumption of from 5 wt.-% to 25 wt.-%,preferably 10 wt.-% to 20 wt.-% of the initially employed monomers.

Monomer conversion can be tracked by online viscometry or spectroscopicmonitoring during the polymerization.

In step A) the organic medium, for example those obtained according tostep b), is contacted with an aqueous medium comprising at least oneLCST compound having a cloud point of 0 to 100□ C, preferably 5 to 100□C, more preferably 15 to 80□ C and even more preferably 20 to 70□ C andremoving at least partially the organic diluent to obtain the aqueousslurry comprising the plurality polyisobutylene particles.

The contact can be performed in any vessel suitable for this purpose. Inindustry such contact is typically performed in a flash drum or anyother vessel known for separation of a liquid phase and vapours.

Removal of organic diluent may also employ other types of distillationso to subsequently or jointly remove the residual monomers and theorganic diluent to the desired extent. Distillation processes toseparate liquids of different boiling points are well known in the artand are described in, for example, the Encyclopedia of ChemicalTechnology, Kirk Othmer, 4th Edition, pp. 8-311, which is incorporatedherein by reference. Generally, the organic diluent may either beseparately or jointly be recycled into a step a) of a polymerizationreaction.

The pressure in step A) and in one embodiment the steam-stripper orflash drum depends on the organic diluent and where applicable,isobutylene employed in step b) but is typically in the range of from100 hPa to 5,000 hPa.

The temperature in step A) is selected to be sufficient to at leastpartially remove the organic diluent and to the extent still presentresidual isobutylene.

In one embodiment the temperature is from 10 to 100□ C, preferably from50 to 100□ C, more preferably from 60 to 95□ C and even more preferablyfrom 75 to 95□ C.

Upon contact of the organic medium with the aqueous medium comprising atleast one LCST compound, the medium is destabilized due to removal ofthe stabilizing organic diluent and in some cases especially where theorganic medium has a temperature below the glass transition temperatureof the polyisobutylene typically rapid heating above the glasstransition temperature of the polyisobutylene thereby formingpolyisobutylene particles suspended in the aqueous slurry.

According to the observations of the applicant and without wanting to bebound by theory a further consequence is that the at least LCST compoundas earlier observed for conventional anti-agglomerants such as calciumstearate, the aqueous medium comprising the at least one LCST compounddepletes from LCST compounds so that in the final aqueous slurry atleast a part, according to the observations disclosed in theexperimental part a substantial part of the LCST compounds are part ofthe polyisobutylene particles and are presumably bound to the surface ofthe polyisobutylene particles causing the tremendous anti-agglomeratingeffect.

Suitable LCST compounds are for example selected from the groupconsisting of: poly(N-isopropylacrylamide),poly(N-isopropylacrylamide-co-N,N-dimethylacrylamide,poly(N-isopropylacrylamide)-alt-2-hydroxyethylmethacrylate,poly(N-vinylcaprolactam), poly(N,N-diethylacrylamide),poly[2-(dimethylamino)ethyl methacrylate], poly(2-oxazoline)glypolyisobutylenes, Poly(3-ethyl-N-vinyl-2-pyrrolidone), hydroxylbutylchitosan, polyoxyethylene (20) sorbitan monostearate, polyoxyethylene(20) sorbitan monolaurate, polyoxyethylene (20) sorbitan monooleate,methyl cellulose, hydroxypropyl cellulose, hydroxyethyl methylcellulose,hydroxypropyl methylcellulose, poly(ethylene glycol) methacrylates with2 to 6 ethylene glycol units, polyethyleneglycol-co-polypropyleneglycols, preferably those with 2 to 6 ethylene glycol units and 2 to 6polypropylene units, compounds of formula (I)HO—[—CH₂—CH₂—O]_(x)—[—CH(CH₃)—CH₂—O]_(y)—[—CH₂—CH₂—O]_(z)—H  (I)with y=3 to 10 and x and z=1 to 8, whereby y+x+z is from 5 to 18,polyethyleneglycol-co-polypropylene glycol, preferably those with 2 to 8ethylene glycol units and 2 to 8 polypropylene units, ethoxylatediso-C₁₃H₂₇-alcohols, preferably with an ethoxylation degree of 4 to 8,polyethylene glycol with 4 to 50, preferably 4 to 20 ethyleneglycolunits, polypropylene glycol with 4 to 30, preferably 4 to 15propyleneglycol units, polyethylene glycol monomethyl, dimethyl,monoethyl and diethyl ether with 4 to 50, preferably 4 to 20ethyleneglycol units, polypropylene glycol monomethyl, dimethyl,monoethyl and diethyl ether with 4 to 50, preferably 4 to 20propyleneglycol units, whereby in another embodiment the aforementionedLCST compounds additionally include hydroxyethylcellulose and wherebymethyl cellulose, hydroxypropyl cellulose, hydroxyethyl methylcelluloseand hydroxypropyl methylcellulose are preferred.

In one embodiment methyl cellulose, hydroxypropyl cellulose,hydroxyethyl methylcellulose and hydroxypropyl methylcellulose have adegree of substitution of from 0.5 to 2.8 the theoretical maximum being3, preferably 1.2 to 2.5 and more preferably 1.5 to 2.0.

In one embodiment hydroxypropyl cellulose, hydroxyethyl methylcelluloseand hydroxypropyl methylcellulose have a MS (moles of substitution) offrom 3, preferably of from 4, more preferably of from 4 to 20 withrespect to ethylene glycol or propylene glycol groups per glucose unit.

The amount of LCST compound(s) present in the aqueous medium employed instep A) is for example of from 1 to 20,000 ppm, preferably 3 to 10,000ppm, more preferably 5 to 5,000 ppm and even more preferably 10 to 5,000ppm with respect to the amount of polyisobutylene present in the organicmedium.

In one embodiment the LCST compounds exhibit a molecular weight of atleast 1,500 g/mol, preferably at least 2,500 g/mol and more preferablyat least 4,000 g/mol.

Where a mixture of different LCST compounds is applied the weightaverage molecular weight is for example of from 1,500 to 2,000,000.

The unique capability of the LCST compounds to stabilize polyisobutyleneparticles in aqueous solution is a major finding of the invention. Theinvention therefore also encompasses a method to prevent or reduce or toslow-down agglomeration of slurries comprising polyisobutylene particlessuspended in aqueous media by addition or use of LCST compounds having acloud point of 0 to 100□ C, preferably 5 to 100□ C, more preferably 15to 80□ C and even more preferably 20 to 70□ C.

For the avoidance of doubt it is noted that the aqueous slurry obtainedin step A) is distinct from and unrelated to the polymerization slurrythat may be obtained in some embodiments described in step b).

In case step b) was carried out as solution polymerization upon contactwith water the organic diluent is evaporated and the polyisobutyleneforms polyisobutylene particles suspended in the aqueous slurry.

The at least partial removal of the organic diluent typically requiressignificant amounts of heat to balance the heat of evaporation which canbe provided for example by heating the vessel wherein step A) isperformed either from outside or in a preferred embodiment additionallyor alternatively by introducing steam which further aids removal oforganic diluent and to the extent still present after polymerization theisobutylene (steam stripping).

Step A) may be carried out batchwise or continuously, whereby acontinuous operation is preferred.

In one embodiment the temperature of the resulting slurry obtained instep A) is from 50 to 100□ C, preferably from 60 to 100□ C, morepreferably from 70 to 95□ C and even more preferably from 75 to 95□ C.

Even found not to be necessary in one embodiment the temperature in stepA) is above the highest determined cloud point of the at least one LCSTscompound employed.

Highest determined cloud point means the highest cloud point measuredwith the five, or in another embodiment three methods disclosed above.If a cloud point cannot be determined for whatever reason with one ortwo methods the highest cloud point of the other determinations is takenas the highest determined cloud point.

In one embodiment the removal of the organic diluent is performed untilthe aqueous slurry comprises less than 10 wt.-% of organic diluentcalculated on the polyisobutylene contained in the polyisobutyleneparticles of the resulting aqueous slurry, preferably less than 7 wt.-%and even more preferably less than 5 wt.-% and yet even more preferablyless than 3 wt.-%.

It was not known before and is highly surprising that an aqueous slurrycomprising a plurality of polyisobutylene particles with very low levelsor even absence of antiagglomerants selected from carboxylic acid saltsof mono- or multivalent metal ions and layered minerals can be obtainedat all.

Therefore, the use of LCST compounds having a cloud point of 0 to 100□C, preferably 5 to 100□ C, more preferably 15 to 80□ C and even morepreferably 20 to 70□ C as anti-agglomerant, in particular forpolyisobutylene particles as defined is encompassed by the invention aswell.

The aqueous slurries disclosed hereinabove and as obtainable accordingto step A) as such are therefore also encompassed by the invention.

The aqueous slurries obtained according to step A) serve as an idealstarting material to obtain the polyisobutylene particles in isolatedform.

Therefore, in a further step C) the polyisobutylene particles containedin the aqueous slurry obtained according to step B) may be separated toobtain the polyisobutylene particles.

The separation may be effected by flotation, centrifugation, filtration,dewatering in a dewatering extruder or by any other means known to thoseskilled in the art for the separation of solids from fluids.

In one embodiment the separated aqueous medium is recycled into step A)if required after replacement of LCST-compounds, water and optionallyother components which were removed with the polyisobutylene particles.

In a further step D) the polyisobutylene particles obtained according tostep C) are dried, preferably to a residual content of volatiles of7,000 or less, preferably 5,000 or less, even more preferably 4,000 orless and in another embodiment 2,000 ppm or less, preferably 1,000 ppmor less.

As used herein the term volatiles denotes compounds having a boilingpoint of below 250□ C, preferably 200□ C or less at standard pressureand include water as well as remaining organic diluents.

Drying can be performed using conventional means known to those in theart, which includes drying on a heated mesh conveyor belt.

Depending on the drying process the polyisobutylene particles may alsobe brought into a different shape hereinafter referred to reshapedpolyisobutylene particles.

Reshaped polyisobutylene particles are for example pellets. Suchreshaped polyisobutylene particles are also encompassed by the inventionand for example obtained by drying in an extruder followed bypelletizing at the extruder outlet. Such pelletizing may also beperformed under water. The process according to the invention allowspreparation of polyisobutylene particles and polyisobutylene productshaving a tunable or if desired an unprecedented low level of mono- andmultivalent metal ions.

The invention therefore encompasses polyisobutylene particles andreshaped polyisobutylene particles having a polyisobutylene content of98.5 wt.-% or more, preferably 98.8 wt.-% or more, more preferably, 99.0wt.-% or more even more preferably 99.2 wt.-% or more, yet even morepreferably 99.4 wt.-% or more and in another embodiment 99.5 wt.-% ormore preferably 99.7 wt.-% or more.

In one embodiment the (reshaped) polyisobutylene particles andpolyisobutylene products comprise 550 ppm or less, preferably 400 ppm orless, more preferably 300 ppm or less, even more preferably 250 ppm orless and yet even more preferably 150 ppm or less and in another yeteven more preferred embodiment 100 ppm or less of salts of mono- ormultivalent metal ions calculated on their metal content and withrespect to the amount of polyisobutylene present in the organic medium.

In one embodiment the (reshaped) polyisobutylene particles comprise 5000ppm or less, preferably 2.000 ppm or less, more preferably 1.000 ppm orless, even more preferably 500 ppm or less and yet even more preferably100 ppm or less and in another yet even more preferred embodiment 50 ppmor less, preferably 50 ppm or less more preferably 10 ppm or less andyet even more preferably no non-LCST compounds selected from the groupconsisting of ionic or non-ionic surfactants, emulsifiers, andantiagglomerants.

In another aspect the invention provides (reshaped) polyisobutyleneparticles comprising salts of multivalent metal ions in an amount of 500ppm or less, preferably 400 ppm or less, more preferably 250 ppm orless, even more preferably 150 ppm or less and yet even more preferably100 ppm or less and in an even more preferred embodiment 50 ppm or lesscalculated on their metal content.

The (reshaped) copolymer particles according to the invention mayfurther comprise antioxidants, e.g. at least one antioxidant of thoselisted above.

Particularly preferred arepentaerythrol-tetrakis-[3-(3,5-di-tert.-butyl-4-hydroxyphenyl)-propanoicacid (also known as Irganox□ 1010) and2,6-di-tert.-butyl-4-methyl-phenol (BHT).

The amount of antioxidant in the (reshaped) copolymer particles is forexample of from 50 ppm to 1000 ppm, preferably of from 80 ppm to 500 ppmand in another embodiment of from 300 ppm to 700 ppm.

Typically the remainder to 100 wt.-% include the LCST compound(s),volatiles, to the extent employed at all salts of multivalent metal ionsas well as low levels of residual monovalent metal ion salts such assodium chloride.

In one embodiment the amount of LCST compounds present in thepolyisobutylene particles and reshaped polyisobutylene particles is from1 ppm to 18,000 ppm, preferably of from 1 ppm to 10,000 ppm, morepreferably 1 ppm to 5,000 ppm, even more preferably from 1 ppm to 2,000ppm and in a more preferred embodiment from 5 to 1,000 ppm or from 5 to500 ppm.

In one embodiment the amount of salts of monovalent metal ions presentin the polyisobutylene particles and reshaped polyisobutylene particlesis from 1 ppm to 1,000 ppm, preferably from 10 ppm to 500 ppm and in amore preferred embodiment from 10 to 200 ppm.

In one embodiment the amount of stearates or palmitates of mono- ormultivalent metal ions present in the polyisobutylene particles andpolyisobutylene products is 0 to 4,000 ppm, preferably 0 to 2,000 ppm,more preferably 0 to 1,000 ppm and in a more preferred embodiment from 0to 500 ppm.

In one embodiment the amount of LCST compounds present in thepolyisobutylene particles and reshaped polyisobutylene particles is from1 ppm to 5,000 ppm, preferably from 1 ppm to 2,000 ppm and in a morepreferred embodiment from 5 to 1,000 ppm or from 5 to 500 ppm.

In another preferred embodiment the amount of LCST compounds present inthe polyisobutylene particles and reshaped polyisobutylene particles isfrom 5 to 100 ppm, preferably from 5 to 50 ppm and more preferably from5 to 30 ppm.

In one embodiment the amount of salts of monovalent metal ions presentin the polyisobutylene particles and reshaped polyisobutylene particlesis from 1 ppm to 1,000 ppm, preferably from 10 ppm to 500 ppm and in amore preferred embodiment from 10 to 200 ppm.

In one embodiment the amount of stearates or palmitates of multivalentmetal ions present in the polyisobutylene particles and reshapedpolyisobutylene particles is 0 to 4,000 ppm, preferably 0 to 2,000 ppm,more preferably 0 to 1,000 ppm and in a more preferred embodiment from 0to 500 ppm.

In one embodiment the invention therefore encompasses polyisobutyleneparticles and polyisobutylene products comprising

-   I) 96.0 wt.-% or more, preferably 97.0 wt.-% or more, more    preferably, 98.0 wt.-% or more even more preferably 99.0 wt.-% or    more, yet even more preferably 99.2 wt.-% or more and in another    embodiment 99.5 wt.-% or more of a polyisobutylene-   II) 0 to 3.0 wt.-%, preferably 0 to 2.5 wt.-%, more preferably 0 to    1.0 wt.-% and more preferably 0 to 0.40 wt.-% of salts of mono- or    multivalent metal ions, preferably stearates and palmitates of    multivalent metal ions and-   III) 1 ppm to 5,000 ppm, preferably from 1 ppm to 2,000 ppm and in a    more preferred embodiment from 5 to 1,000 ppm or from 5 to 500 ppm    of at least one LCST compound.

Where an LCST compound is defined as a mandatory component the inventionnot only encompasses polyisobutylene particles or reshapedpolyisobutylene particles herein jointly referred to as (reshaped)polyisobutylene particles but any type of polyisobutylene compositioncomprising the LCST compounds.

In another embodiment the invention therefore encompasses apolyisobutylene composition, in particular (reshaped) polyisobutyleneparticles comprising

-   I) 96.0 wt.-% or more, preferably 97.0 wt.-% or more, more    preferably, 98.0 wt.-% or more even more preferably 99.0 wt.-% or    more, yet even more preferably 99.2 wt.-% or more and in another    embodiment 99.5 wt.-% or more of polyisobutylene-   II) 0 to 3.0 wt.-%, preferably 0 to 2.5 wt.-%, more preferably 0 to    1.0 wt.-% and more preferably 0 to 0.40 wt.-% of salts of mono- or    multivalent metal ions, preferably stearates and palmitates of    multivalent metal ions and-   III) 1 ppm to 5,000 ppm, preferably from 1 ppm to 2,000 ppm and in a    more preferred embodiment from 5 to 1,000 ppm or from 5 to 500 ppm    of at least one LCST compound

Since salts of multivalent metal ions contribute to the ash contentmeasurable according to ASTM D5667 (reapproved version 2010) theinvention further encompasses a polyisobutylene composition, inparticular (reshaped) polyisobutylene particles comprising 98.5 wt.-% ormore, preferably 98.8 wt.-% or more, more preferably 99.0 wt.-% or moreeven more preferably 99.2 wt.-% or more, yet even more preferably 99.4wt.-% or more and in another embodiment 99.5 wt.-% or more ofpolyisobutylene and having an ash content measured according to ASTMD5667 of 0.2 wt.-% or less, preferably 0.1 wt.-% or less, morepreferably 0.08 wt.-% or less and even more preferably 0.05 wt.-% orless, yet even more preferably 0.03 wt.-% or less and most preferably0.015 wt.-% or less.

In a preferred embodiment the aforementioned polyisobutylenecomposition, in particular (reshaped) copolymer particles furthercomprise 1 ppm to 5,000 ppm, preferably from 1 ppm to 2,000 ppm and in amore preferred embodiment from 5 to 1,000 ppm or from 5 to 500 ppm of aleast one LCST compound.

In yet another embodiment the invention encompasses a polyisobutylenecomposition, in particular (reshaped) polyisobutylene particles andpolyisobutylene products comprising

-   I) 100 parts by weight of polyisobutylene (100 phr)-   II) 0.0001 to 0.5, preferably 0.0001 to 0.2, more preferably 0.0005    to 0.1, even more preferably 0.0005 to 0.05 phr of a least one LCST    compound and-   III) no or from 0.0001 to 3.0, preferably no or from 0.0001 to 2.0,    more preferably no or from 0.0001 to 1.0, even more preferably no or    from 0.0001 to 0.5, yet even more preferably no or from 0.0001 to    0.3, and most preferably no or from 0.0001 to 0.2 phr of salts of    mono- or multivalent metal ions, preferably stearates and palmitates    of mono- or multivalent metal ions, preferably comprising calcium    stearate, calcium palmitate, zinc stearate or zinc palmitate and-   IV) no or from 0.005 to 0.1, preferably from 0.008 to 0.05, more    preferably from 0.03 to 0.07 phr of antioxidants-   V) from 0.005 to 0.5, preferably from 0.01 to 0.3, more preferably    from 0.05 to 0.2 phr of volatiles having a boiling point at standard    pressure of 200□ C or less.

Preferably the aforementioned components I) to V) add up to 100.00501 to104.100000 parts by weight, preferably from 100.01 to 103.00 parts byweight, more preferably from 100.10 to 101.50 parts by weight, even morepreferably from 100.10 to 100.80 parts by weight and together represent99.80 to 100.00 wt.-%, preferably 99.90 to 100.00 wt.-%, more preferably99.95 to 100.00 wt.-% and yet even more preferably 99.97 to 100.00 wt.-%of the total weight of the polyisobutylene composition, in particular(reshaped) polyisobutylene particles.

The remainder, if any, may represent salts or components which are noneof the aforementioned components and e.g. stemming from the wateremployed to prepare the aqueous medium used in step A) or, ifapplicable, products including decomposition products and saltsremaining from the initiator system employed in step b).

Determination of free carboxylic acids and their salts, in particularcalcium and zinc stearate or palmitate can be accomplished bymeasurement using Gas Chromatography with a Flame Ionization Detector(GC-FID) according to the following procedure:

2 g of a sample of copolymer composition are weighed to the nearest0.0001 g, placed in a 100 mL jar and combined with

-   -   a) 25 mL hexane, 1,000 mL of an internal standard solution where        levels of free carboxylic acids are to be determined and    -   b) 25 mL hexane, 1,000 mL of an internal standard solution and 5        drops of concentrated sulfuric acid where levels of carboxylic        acid salts are to be determined.

The jar is put on a shaker for 12 hours. Then 23 ml acetone are addedand the remaining mixture evaporated to dryness at 50□ C which takestypically 30 minutes. Thereafter 10 ml methanol and 2 drops ofconcentrated sulfuric acid are added, shaken to mix and heated for 1hour to 50□ C to convert the carboxylic acids into their methyl esters.Thereafter 10 ml hexane and 10 ml demineralized water are added,vigorously shaken and finally the hexane layer is allowed to separate. 2ml of the hexane solution are used for GC-FID analysis.

It is known to those skilled in the art that technical stearates such ascalcium and zinc stearate also contain fractions of other calcium andzinc carboxylic acid salts such as palmitates. However, GC-FID allows todetermine the contents of other carboxylic acids as well.

Direct measurement of carboxylic acid salts in particular stearates andpalmitates can be accomplished by FTIR as follows: A sample of rubber ispressed between two sheets of silicon release paper in a paper sampleholder and analyzed on an infrared spectrometer. Calcium stearatecarbonyl peaks are found at 1541.8 &1577.2 cm⁻¹. The peaks of heatconverted calcium stearate (a different modification of calciumstearate, see e.g. Journal of Colloid Science Volume 4, Issue 2, April1949, Pages 93□ 101) are found at 1562.8 and 1600.6 cm⁻¹ and are alsoincluded in the calcium stearate calculation. These peaks are ratioed tothe peak at 950 cm⁻¹ to account for thickness variations in the samples.

By comparing peak heights to those of known standards with predeterminedlevels of calcium stearate, the concentrations of calcium stearate canbe determined. The same applies to other carboxylic acid salts inparticular stearates and palmitates as well. For example, a single zincstearate carbonyl peak is found at 1539.5 cm⁻¹, for sodium stearate asingle carbonyl peak is found at 1558.5 cm⁻¹.

Contents of mono- or multivalent metal ions, in particular multivalentmetal ions such as calcium and zinc contents can generally be determinedand were determined if not mentioned otherwise by Inductively coupledplasma atomic emission spectrometry (ICP-AES) according to EPA 6010Method C using NIST traceable calibration standards after microwavedigestion according to EPA 3052 method C.

Additionally or alternatively contents of various elements can bedetermined by X-ray fluorescence (XRF). The sample is irradiated withX-ray radiation of sufficient energy to excite the elements of interest.The elements will give off energy specific to the element type which isdetected by an appropriate detector. Comparison to standards of knownconcentration and similar matrix will give quantitation of the desiredelement. Contents of LCST compounds, in particular methyl cellulosecontents are measurable and were measured using Gel FiltrationChromatography on a Waters Alliance 2690/5 separations module equippedwith a PolySep-GFC-P4000, 300×7.8 mm aqueous GFC column and aPolySep-GFC-P4000, 35×7.8 mm guard column and a Waters 2414 DifferentialRefractometer against standards of known concentration. As gelfiltration chromatography separates based on molecular weight, it may benecessary to employ different columns than those mentioned above inorder to analyze for LCST compounds across different molecular weightranges.

The samples are for example prepared according to the followingprocedure:

2 g of a sample of copolymer compositions are weighed to the nearest0.0001 g and dissolved in 30 ml hexanes using a shaker at low speedovernight in a closed vial. Exactly 5 ml of HPLC grade water at roomtemperature are added, the vial is recapped and shaken another 30minutes. After phase separation the aqueous phase was used for GelFiltration Chromatography and injected via a 0.45 micron syringe filter.

It is apparent to those skilled in the art that different analyticalmethods may result in slightly different results. However, at least tothe extent above methods are concerned, the results were found to beconsistent within their specific and inherent limits of error.

For all polyisobutylene compositions described above in one embodiment,the ash content measured according to ASTM D5667 is for example 0.2wt.-% or less, preferably 0.1 wt.-% or less, more preferably 0.08 wt.-%or less and even more preferably 0.05 wt.-% or less, yet even morepreferably 0.03 wt.-% or less and most preferably 0.015 wt.-% or less.

Preferred polyisobutylenes are those already described in the processsection above.

In one embodiment the polyisobutylene particles and polyisobutyleneproducts exhibit a bulk density of from 0.05 kg/l to 0.900 kg/l.

In a further step e) the polyisobutylene particles obtained in step f)are subjected to a shaping process such as baling.

The invention therefore encompasses a shaped article in particular abale obtainable by shaping, in particular baling the polyisobutyleneparticles and polyisobutylene products obtained in step d). Shaping canbe performed using any standard equipment known to those skilled in theart for such purposes. Baling can e.g. performed with conventional,commercially available balers. The shaped articles made from orcomprising (reshaped) polyisobutylene particles are encompassed by theterm polyisobutylene compositions as well.

In one embodiment the shaped article in particular the bale exhibits adensity of from 0.700 kg/l to 0.850 kg/l.

In another embodiment the shaped article is cuboid and has a weight offrom 10 to 50 kg, preferably 25 to 40 kg.

It is apparent for those skilled in the art, that the density of theshaped article in particular the bale is higher than the bulk density ofthe polyisobutylene particles employed for its production.

Blends

The polyisobutylene compositions, in particular the (reshaped)polyisobutylene particles and shaped articles made from or comprising(reshaped) polyisobutylene particles are hereinafter referred to as thepolyisobutylenes according to the invention. One or more of thepolyisobutylenes according to the invention may be blended either witheach other or additionally or alternatively with at least one secondaryrubber being different from the polyisobutylene forming thepolyisobutylene particles which is preferably selected from the groupconsisting of natural rubber (NR), epoxidized natural rubber (ENR),polyisoprene rubber, poly(styrene-co-butadiene) rubber (SBR),chloroprene rubber (CR), polybutadiene rubber (BR),perfluoropolyisobutylene (FFKM/FFPM), ethylene vinylacetate (EVA)rubber, ethylene acrylate rubber, polysulphide rubber (TR),poly(isoprene-co-butadiene) rubber (IBR), styrene-isoprene-butadienerubber (SIBR), ethylene-propylene rubber (EPR), ethylene-propylene-dieneM-class rubber (EPDM), polyphenylensulfide, nitrile-butadiene rubber(NBR), hydrogenated nitrile-butadiene rubber (HNBR), propylene oxidepolymers, star-branched butyl rubber and halogenated star-branched butylrubber, butyl rubbers which are not subject of the present inventioni.e. having i.a. different levels of multivalent metal ions or puritygrages, brominated butyl rubber and chlorinated butyl rubber,star-branched polyisobutylene rubber, star-branched brominated butyl(polyisobutylene/isoprene polyisobutylene) rubber;poly(isobutylene-co-p-methylstyrene) and halogenatedpoly(isobutylene-co-p-methylstyrene), halogenatedpoly(isobutylene-co-isoprene-co-p-methylstyrene),poly(isobutylene-co-isoprene-co-styrene), halogenatedpoly(isobutylene-co-isoprene-co-styrene),poly(isobutylene-co-isoprene-co-alpha-methylstyrene), halogenatedpoly(isobutylene-co-isoprene-co-a-methylstyrene).

One or more of the polyisobutylenes according to the invention or theblends with secondary rubbers described above may be further blendedadditionally or alternatively for example simultaneously or separatelywith at least one thermoplastic polymer, which is preferably selectedfrom the group consisting of polyphenylsulfide (PPS), polyurethane (PU),polyacrylic esters (ACM, PMMA), thermoplastic polyester urethane (AU),thermoplastic polyether urethane (EU), perfluoroalkoxyalkane (PFA),polytetrafluoroethylene (PTFE), and polytetrafluoroethylene (PTFE).

One or more of the polyisobutylenes according to the invention or theblends with secondary rubbers and/or thermoplastic polymers describedabove may be compounded with one or more fillers. The fillers may benon-mineral fillers, mineral fillers or mixtures thereof. Non-mineralfillers are preferred in some embodiments and include, for example,carbon blacks, rubber gels and mixtures thereof. Suitable carbon blacksare preferably prepared by lamp black, furnace black or gas blackprocesses. Carbon blacks preferably have BET specific surface areas of20 to 200 m²/g. Some specific examples of carbon blacks are SAF, ISAF,HAF, FEF and GPF carbon blacks. Rubber gels are preferably those basedon polybutadiene, butadiene/styrene polyisobutylenes,butadiene/acrylonitrile polyisobutylenes or polychloroprene.

Suitable mineral fillers comprise, for example, silica, silicates, clay,bentonite, vermiculite, nontronite, beidelite, volkonskoite, hectorite,saponite, laponite, sauconite, magadiite, kenyaite, ledikite, gypsum,alumina, talc, glass, metal oxides (e.g. titanium dioxide, zinc oxide,magnesium oxide, aluminum oxide), metal carbonates (e.g. magnesiumcarbonate, calcium carbonate, zinc carbonate), metal hydroxides (e.g.aluminum hydroxide, magnesium hydroxide) or mixtures thereof.

Dried amorphous silica particles suitable for use as mineral fillers mayhave a mean agglomerate particle size in the range of from 1 to 100microns, or 10 to 50 microns, or 10 to 25 microns. In one embodiment,less than 10 percent by volume of the agglomerate particles may be below5 microns. In one embodiment, less than 10 percent by volume of theagglomerate particles may be over 50 microns in size. Suitable amorphousdried silica may have, for example, a BET surface area, measured inaccordance with DIN (Deutsche Industrie Norm) 66131, of between 50 and450 square meters per gram. DBP absorption, as measured in accordancewith DIN 53601, may be between 150 and 400 grams per 100 grams ofsilica. A drying loss, as measured according to DIN ISO 787/11, may befrom 0 to 10 percent by weight. Suitable silica fillers are commerciallysold under the names HiSil□ 210, HiSil□ 233 and HiSil□ 243 availablefrom PPG Industries Inc. Also suitable are Vulkasil□ S and Vulkasil□ N,commercially available from Bayer AG.

High aspect ratio fillers useful in the present invention may includeclays, talcs, micas, etc. with an aspect ratio of at least 1:3. Thefillers may include acircular or nonisometric materials with a platy orneedle-like structure. The aspect ratio is defined as the ratio of meandiameter of a circle of the same area as the face of the plate to themean thickness of the plate. The aspect ratio for needle and fibershaped fillers is the ratio of length to diameter. The high aspect ratiofillers may have an aspect ratio of at least 1:5, or at least 1:7, or ina range of 1:7 to 1:200. High aspect ratio fillers may have, forexample, a mean particle size in the range of from 0.001 to 100 microns,or 0.005 to 50 microns, or 0.01 to 10 microns. Suitable high aspectratio fillers may have a BET surface area, measured in accordance withDIN (Deutsche Industrie Norm) 66131, of between 5 and 200 square metersper gram. The high aspect ratio filler may comprise a nanoclay, such as,for example, an organically modified nanoclay. Examples of nanoclaysinclude natural powdered smectite clays (e.g. sodium or calciummontmorillonite) or synthetic clays (e.g. hydrotalcite or laponite). Inone embodiment, the high aspect filler may include organically modifiedmontmorillonite nanoclays. The clays may be modified by substitution ofthe transition metal for an onium ion, as is known in the art, toprovide surfactant functionality to the clay that aids in the dispersionof the clay within the generally hydrophobic polymer environment. In oneembodiment, onium ions are phosphorus based (e.g. phosphonium ions) ornitrogen based (e.g. ammonium ions) and contain functional groups havingfrom 2 to 20 carbon atoms. The clays may be provided, for example, innanometer scale particle sizes, such as, less than 25 μm by volume. Theparticle size may be in a range of from 1 to 50 μm, or 1 to 30 μm, or 2to 20 μm. In addition to silica, the nanoclays may also contain somefraction of alumina. For example, the nanoclays may contain from 0.1 to10 Wt.-% alumina, or 0.5 to 5 Wt.-% alumina, or 1 to 3 Wt.-% alumina.Examples of commercially available organically modified nanoclays ashigh aspect ratio mineral fillers include, for example, those sold underthe trade name Cloisite□ clays 10A, 20A, 6A, 15A, 30B, or 25A.

One or more of the polyisobutylenes according to the invention or theblends with secondary rubbers and/or thermoplastic polymers or thecompounds described above are hereinafter collectively referred to aspolymer products and may further contain other ingredients such ascuring agents, reaction accelerators, vulcanizing accelerators,vulcanizing acceleration auxiliaries, antioxidants, foaming agents,anti-aging agents, heat stabilizers, light stabilizers, ozonestabilizers, processing aids, plasticizers, tackifiers, blowing agents,dyestuffs, pigments, waxes, extenders, organic acids, inhibitors, metaloxides, and activators such as triethanolamine, polyethylene glycol,hexanetriol, etc., which are known to the rubber industry. Theseingredients are used in conventional amounts that depend, inter alia, onthe intended use.

Applications

It was found that the polymer products are particularly useful for thepreparation of compounds for specific applications.

Such applications include sealants, adhesives, coatings and roofings.

Therefore, the invention also encompasses the use of thepolyisobutylenes according to the invention in or as sealants,adhesives, coatings and roofings.

The polymer products are also useful in tire sidewalls and treadcompounds. In sidewalls, the polyisobutylenes characteristics impartgood ozone resistance, crack cut growth, and appearance.

In a preferred specific embodiment 1, the invention relates to a processfor the preparation of an aqueous slurry comprising a plurality ofelastomer particles suspended therein, the process comprising at leastthe step of:

A*) contacting an organic medium comprising

i) at least one elastomer and

ii) an organic diluent

with an aqueous medium comprising at least one LCST compound having acloud point of 0 to 100□ C, preferably 5 to 100□ C, more preferably 15to 80□ C and even more preferably 20 to 70□ C

and

removing at least partially the organic diluent to obtain the aqueousslurry comprising the elastomer particles, whereby the elastomer ispolyisobutylene.

-   1. In a specific embodiment 2 according to specific embodiment 1 the    organic medium comprising at least polyisobutylene and an organic    diluent is obtained from a polymerization reaction or a    post-polymerization.-   2. In a specific embodiment 3 according to specific embodiment 1 or    2 the organic medium is obtained from a polymerization reaction and    further contains residual monomers of the polymerization reaction.

In a specific embodiment 4 according to one of specific embodiments 1 to3 the aqueous medium contains of from 0 to 5,000 ppm, preferably of from0 to 2,000 ppm, more preferably of from 10 to 1,000 ppm, even morepreferably of from 50 to 800 ppm and yet even more preferably of from100 to 600 ppm of salts of multivalent metal ions calculated on theirmetal content and with respect to the amount of polyisobutylene presentin the medium obtained according to step A).

In a specific embodiment 5 according to one of specific embodiments 1 to4 the aqueous medium comprises 550 ppm or less, preferably 400 ppm orless, more preferably 300 ppm or less, even more preferably 250 ppm orless and yet even more preferably 150 ppm or less and in another yeteven more preferred embodiment 100 ppm or less of carboxylic acid saltsof multivalent metal ions calculated on their metal content and withrespect to the amount of polyisobutylene present in the medium obtainedaccording to step b).

In a specific embodiment 6 according to specific embodiments 4 or 5 thesalts of multivalent metal ions are calcium stearate and/or zincstearate and/or calcium palmitate and/or zinc palmitate.

In a specific embodiment 7 according to specific embodiment 6 thecarboxylic acid salts of multivalent metal ions are calcium stearateand/or zinc stearate and/or calcium palmitate and/or zinc palmitate.

In a specific embodiment 8 according to one of specific embodiments 1 to7 the organic medium comprising at least one elastomer and an organicdiluent is obtained from a polymerization reaction comprising at leastthe steps of:

-   a) providing a reaction medium comprising an organic diluent, and at    least one polymerizable monomer-   b) polymerizing the monomers within the reaction medium in the    presence of an initiator system or catalyst to form an organic    medium comprising the elastomer, the organic diluent and optionally    residual monomers.

In a specific embodiment 9 according to one of specific embodiments 1 to8 step A*) is carried out batchwise or continuously, preferablycontinuously.

In a specific embodiment 10 according to one of specific embodiments 1to 9 the temperature in step A*) is from 10 to 100□ C, preferably from50 to 100□ C, more preferably from 60 to 95□ C and even more preferablyfrom 75 to 95□ C.

In a specific embodiment 11 according to one of specific embodiments 1to 10 the at least one LCST compound is selected from the groupconsisting of:

poly(N-isopropylacrylamide),poly(N-isopropylacrylamide-co-N,N-dimethylacrylamide,poly(N-isopropylacrylamide)-alt-2-hydroxyethylmethacrylate,poly(N-vinylcaprolactam), poly(N,N-diethylacrylamide),poly[2-(dimethylamino)ethyl methacrylate], poly(2-oxazoline)glyelastomers, Poly(3-ethyl-N-vinyl-2-pyrrolidone), hydroxylbutylchitosan, polyoxyethylene (20) sorbitan monostearate, polyoxyethylene(20) sorbitan monolaurate, polyoxyethylene (20) sorbitan monooleate,methyl cellulose, hydroxypropyl cellulose, hydroxyethyl methylcellulose,hydroxypropyl methylcellulose, poly(ethylene glycol) methacrylates with2 to 6 ethylene glycol units, polyethyleneglycol-co-polypropyleneglycols, preferably those with 2 to 6 ethylene glycol units and 2 to 6polypropylene units, compounds of formula (I)HO—[—CH₂—CH₂—O]_(x)—[—CH(CH₃)—CH₂—O]—[—CH₂—CH₂—O]_(z)—H  (I)with y=3 to 10 and x and z=1 to 8, whereby y+x+z is from 5 to 18,polyethyleneglycol-co-polypropylene glycol, preferably those with 2 to 8ethylene glycol units and 2 to 8 polypropylene units, ethoxylatediso-C₁₃H₂₇-alcohols, preferably with an ethoxylation degree of 4 to 8,polyethylene glycol with 4 to 50, preferably 4 to 20 ethyleneglycolunits, polypropylene glycol with 4 to 30, preferably 4 to 15propyleneglycol units, polyethylene glycol monomethyl, dimethyl,monoethyl and diethyl ether with 4 to 50, preferably 4 to 20ethyleneglycol units, polypropylene glycol monomethyl, dimethyl,monoethyl and diethyl ether with 4 to 50, preferably 4 to 20propyleneglycol units, whereby methyl cellulose, hydroxypropylcellulose, hydroxyethyl methylcellulose and hydroxypropylmethylcellulose are preferred.

In a specific embodiment 12 according to one of specific embodiments 1to 11 the process comprises a further step wherein the elastomerparticles contained in the aqueous slurry obtained according to step A*)are separated to obtain isolated elastomer particles.

In a specific embodiment 13 according to one of specific embodiments 1to 11 the process comprises a further step wherein the elastomerparticles contained in the aqueous slurry obtained according to step A*)are separated to obtain isolated elastomer particles and further stepwherein the (isolated) elastomer particles are dried, preferably to aresidual content of volatiles of 7,000 or less, preferably 5,000 orless, even more preferably 4,000 or less and in another embodiment 2,000ppm or less, preferably 1,000 ppm or less.

In a specific embodiment 14 according to one of specific embodiments 1to 12 the process comprises as a further step shaping of the elastomerparticles to obtain reshaped elastomer particles such as pellets orshaped articles such as bales.

In a specific embodiment 15 the invention encompasses an aqueous slurryobtainable according to one of specific embodiments 1 to 14.

In a specific embodiment 16 the invention encompasses the use of LCSTcompounds having a cloud point of 0 to 100□ C, preferably 5 to 100□ C,more preferably 15 to 80□ C and even more preferably 20 to 70□ C asdefined in specific embodiment 1 as anti-agglomerant, in particular forpolyisobutylene particles.

In a specific embodiment 17 the invention encompasses a method toprevent or reduce or to slow-down agglomeration of slurries comprisingpolyisobutylene particles suspended in aqueous media by addition or useof LCST compounds having a cloud point of 0 to 100□ C, preferably 5 to100□ C, more preferably 15 to 80□ C and even more preferably 20 to 70□ Cas defined in specific embodiment 1.

In a specific embodiment 18 the invention encompasses polyisobutyleneparticles having a polyisobutylene content of 98.5 wt.-% or more,preferably 98.8 wt.-% or more, more preferably 99.0 wt.-% or more evenmore preferably 99.2 wt.-% or more, yet even more preferably 99.4 wt.-%or more and in another embodiment 99.5 wt.-% or more.

In a specific embodiment 19 according to specific embodiment 18 thepolyisobutylene has a weight average molecular weight in the range offrom 10 to 2,000 kg/mol, preferably in the range of from 20 to 1,000kg/mol, more preferably in the range of from 50 to 1,000 kg/mol, evenmore preferably in the range of from 200 to 800 kg/mol, yet morepreferably in the range of from 375 to 550 kg/mol, and most preferablyin the range of from 400 to 500 kg/mol.

In a specific embodiment 20 according to specific embodiments 18 or 19the polyisobutylene has a Mooney viscosity of at least 10 (ML 1+8 at125□ C, ASTM D 1646), preferably of from 20 to 80 and even morepreferably of from 25 to 60 (ML 1+8 at 125□ C, ASTM D 1646).

In a specific embodiment 21 according to one of specific embodiments 18to 20 the polyisobutylene particles further comprise 0 to 0.4 wt.-%,preferably 0 to 0.2 wt.-%, more preferably 0 to 0.1 wt.-% and morepreferably 0 to 0.05 wt.-% of salts of multivalent metal ions,preferably stearates and palmitates of multivalent metal ions.

In a specific embodiment 22 according to one of specific embodiments 18to 21 the polyisobutylene particles further comprise 1 ppm to 18,000ppm, preferably 1 ppm to 5,000 ppm, more preferably from 1 ppm to 2,000ppm and in a more preferred embodiment from 5 to 1,000 ppm or from 5 to500 ppm of at least one LCST compound.

In a specific embodiment 23 the invention encompasses a shaped article,in particular a pellet or bale obtainable by shaping polyisobutyleneparticles according to specific embodiments 18 to 22.

In a specific embodiment 24 the invention encompasses blends orcompounds obtainable by blending or compounding the polyisobutyleneparticles according to specific embodiments 18 to 22 or the shapedarticles of specific embodiment 23.

In a specific embodiment 25 the invention encompasses the use of thepolyisobutylene particles according to specific embodiments 18 to 22 orthe shaped articles of specific embodiment 23 or the blends or compoundsaccording to specific embodiment 24 for innerliners, bladders, tubes,air cushions, pneumatic springs, air bellows, accumulator bags, hoses,conveyor belts and pharmaceutical closures, automobile suspensionbumpers, auto exhaust hangers, body mounts, shoe soles, tire sidewallsand tread compounds, belts, hoses, shoe soles, gaskets, o-rings,wires/cables, membranes, rollers, bladders (e.g. curing bladders), innerliners of tires, tire treads, shock absorbers, machinery mountings,balloons, balls, golf balls, protective clothing, medical tubing,storage tank linings, electrical insulation, bearings, pharmaceuticalstoppers, adhesives, a container, such as a bottle, tote, storage tank,a container closure or lid; a seal or sealant, such as a gasket orcaulking; a material handling apparatus, such as an auger or conveyorbelt; a cooling tower; a metal working apparatus, or any apparatus incontact with metal working fluids; an engine component, such as fuellines, fuel filters, fuel storage tanks, gaskets, seals, etc.; amembrane, for fluid filtration or tank sealing.

The invention also encompasses specific embodiments which arecombinations of the 25 specific embodiments listed hereinabove withgeneral embodiments, including any level of preferred embodiments,ranges parameters as disclosed above.

The invention is hereinafter further explained by the examples withoutbeing limited thereto.

EXPERIMENTAL SECTION Examples 1 and 2

A polyisobutylene cement was prepared by dissolving of polyisobutylenehaving a weight average molecular weight of 750,000, a viscosity averagemolecular weight of 800,000 and a polydispersity of 5.0 in hexanes (˜80%n-hexane, remainder being branched hexane isomers). The totalconcentration of polyisobutylene in the cement was 5 wt.-%. This cement(71 g, in total 3.55 g based on the mass of polyisobutylene) was pumpedusing a peristaltic pump at a flow rate of 50 mL per minute into anagitated vessel containing

-   Exp. 1): 2 l deionized water at a temperature of 65□ C at    atmospheric pressure-   Exp. 2): 2 l deionized water comprising 0.01 g (or 0.12 wt % with    respect to polyisobutylene) of methyl cellulose.

Low pressure steam (approximately 5-10 psi) was injected into the cementstream at the point of cement entry into the water vessel.

For Exp. 1 a coarse agglomerate is formed, in Exp. 2 separatepolyisobutylene crumb is obtained.

The methyl cellulose employed was methyl cellulose type M 0512 purchasedby Sigma Aldrich having a viscosity of 4000 cp at 2 wt.-% in water and20□ C and a molecular weight of 88,000, a degree of substitution of from1.5 to 1.9 and methoxy substitution of 27.5 to 31.5 wt.-%.

It exhibited a cloud point of 39.0□ C determined by method 5) and acloud point of 37.8□ C determined by method 4).

Examples 3a to 3c Continuous Polyisobutylene Particle Formation

Isobutylene was combined with methyl chloride and optionallydiisobutylene to prepare a polymerization feedstock such that the totalconcentration of the monomer was from approximately 15 to 18 wt.-% withdiisobutylene added in an amount of from 0 to 0.1 wt.-% of theisobutylene content. This feedstock stream was cooled to approximately−100□ C and was fed continuously into an agitated reaction vessel, alsomaintained at −100□ C. In the reaction vessel the feedstock was mixedwith a continuously added initiator system stream, a solution of 0.05 to0.5 wt.-% aluminium trichloride in methyl chloride which was activatedby water in a molar ratio of from 0.1:1 to 1:1 water to aluminiumtrichloride. The addition rates of the feedstock stream and theinitiator system stream were adjusted in a usual manner to provide apolyisobutylene with a viscosity average molecular weight M_(v) ofbetween 250,000 g/mol and 3,000,000 g/mol. Typically, the wt.-ratio ofmonomers in the feedstream to aluminum trichloride was held within arange of 500 to 20000, preferably 1500 to 10000.

Diisobutylene (DIB) was added as a chain transfer agent in order tocontrol the molecular weight of the polymer. Thus, the amount of DIBvaries depending on the molecular weight desired for the final product.For the highest molecular weights, no DIB is required, and sequentiallymore DIB is added within the bounds described above to lower themolecular weight.

Within the agitated reaction vessel the polyisobutylene was obtained inthe form of a finely divided slurry suspended in methyl chloride.

The reaction vessel was set up and operated such that the continuousaddition of feedstock exceeds the volume of the reactor. When thisvolume was exceeded, the well mixed reaction slurry containing methylchloride, unreacted monomers and polyisobutylene was allowed to overflowinto another agitated vessel containing water heated from 65 to 100 andemployed in an amount of from 15:1 to 6:1 by weight calculated on thepolyisobutylene. Thereby the vast majority of the diluent methylchloride was removed from the slurry.

After solvent and monomer stripping was complete, 100 to 500 ppm ofIrganox□ 1010 with respect to polyisobutylene was added to the aqueousmedium prior to the dewatering and finishing of the polymer. It is alsopossible to add this antioxidant earlier in the stripping process, oreven directly to the finishing process after dewatering.

The addition of 50 to 500 ppm of methyl cellulose calculated on thepolyisobutylene allowed for the formation of an aqueous slurry ofpolyisobutylene particles, whereby the concentration of copolymerparticles in the aqueous slurry increased as the polymerizationproceeded. The aqueous slurry was then dewatered and dried usingconventional means to provide a copolymer suitable for testing andanalysis.

Higher or lower values were not tested in this experiment, however thebehavior indicated levels above or below this range can be successfullyemployed depending on the desired adhesion of the polyisobutylene in theaqueous medium.

The methyl cellulose employed had a solution viscosity at 2 wt.-%solution of 3000-5600 cps, molecular weight Mw of ˜90,000, a methoxysubstitution of 27.5□31.5 wt.-% and thus a degree of substitution ofaround 1.9.

It exhibited a cloud point of 39.0□ C determined by method 5) and acloud point of 37.8□ C determined by method 4):

5: DIN EN 1890 of September 2006, method A wherein the amount ofcompound tested is reduced from 1 g per 100 ml of distilled water to 0.2g per 100 ml of distilled water.

4: DIN EN 1890 of September 2006, method A wherein the amount ofcompound tested is reduced from 1 g per 100 ml of distilled water to0.04 g per 100 ml of distilled water.

Using the experimental setup, described before, three products wereobtained after separating the particles from the aqueous slurry anddrying, differentiated by their range of Mv.

Viscosity average molecular weight was determined using an Ubbelohdeviscometer to measure the viscosity of a solution of polyisobutylene inisooctane, which is compared to known values. The test was performed asfollows:

A sample of polyisobutylene (0.0400+/−0.0050 g) is dissolved in 20 mL ofisooctane. 11 mL of this solution is transferred to an Ubbelohdeviscometer which is then allowed to equilibrate in a temperaturecontrolled bath at 20□ C for 10 mins. Using a pipette bulb, the solutionis pulled into the reservoir above the start timer of the viscometer.Then the pipette bulb was removed to allow the solution to flow.

Time, t, is measured as the time in seconds for the meniscus to travelfrom the start line to the stop line of the viscometer. This measurementis taken in triplicate and the averaged value is compared to a table ofknown viscosities in order to determine Mv

The analytical data for the three products obtained is set forth below:

Generally, if not mentioned otherwise, all analytical data was obtainedaccording to the procedures set forth in the description hereinabove.

Molecular weights and polydispersity were determined by gel permeationchromatography in tetrahydrofurane and reported in kg mol⁻¹. The contentof sterically hindered phenolic anti-oxidant (Irganox□ 1010) wasdetermined by HPLC, results are reported in wt. %. Total unsaturationand microstructure were determined of respective signals from ¹H NMRspectra are reported in mol %.

Example 3a

Total unsaturation: <0.04 mol %

Mv: 620,000□950,000 g/mol, with a specific run (SR) having an Mv of819,400

Polydispersity SR (Mw/Mn): 1.71

Calcium: <50 ppm, SR: 24 ppm

Calcium stearate content: below detectable limits (all)

Methyl cellulose content: <0.05 wt.-%

Irganox□ 1010: 0.030□0.100 wt.-%

Volatiles SP: 0.048 wt.-%

Other antiagglomerants, surfactants, emulsifiers: none

Ions: (ICP-AES)

Aluminum SR (from catalyst): 17 ppm

Magnesium SR: 32 ppm

Other multivalent metal ions SR (Mn, Pb, Cu, Cr, Ba, Fe, Zn): 24 ppm

Monovalent metal ions SR (Na, K): 29 ppm

Total Ash SR: (ASTM D5667) 0.008 wt.-%

Example 3b

Total unsaturation: <0.04 mol-%

Mv: 1,000,000□1,350,000 g/mol

Calcium: <50 ppm

Calcium stearate content: below detectable limits

Methyl cellulose content: <0.05 wt.-%

Irganox□ 1010: 0.030□0.100 wt.-%

Volatiles: 0.3 wt.-%

Example 3c

Total unsaturation: <0.04 mol-%

Mv: 2,300,000□2,850,000 g/mol

Calcium: <50 ppm

Calcium stearate content: below detectable limits

Methyl cellulose content: <0.05 wt.-%

Irganox□ 1010: 0.030□0.100 wt.-%

Volatiles: 0.3 wt.-%

For products 3b and 3c the ash content was found to be less than 0.2wt.-% as well.

Thus the polyisobutylene particles according to examples 3a to 3ccomprised:

-   I) 100 parts by weight of polyisobutylene (100 phr)-   II) <0.005 phr of a least one LCST compound and-   III) less than 0.001 phr of non-LCST compounds selected from the    group consisting of ionic or non-ionic surfactants, emulsifiers, and    anti-agglomerants and-   IV) 0.03 to 0.1 phr of antioxidants-   V) around 0.3 phr of volatiles having a boiling point at standard    pressure of 200□ C or less    whereby these components made up more than 99.9 wt-% of the total    weight of the polyisobutylene particles.

Examples 4 to 7

A polyisobutylene cement was prepared by dissolving of 2.8 g ofpolyisobutylene in 765 ml hexanes (˜80% n-hexane, remainder beingbranched hexane isomers). The total concentration of polyisobutylene inthe cement was around 2.5 wt.-%. This cement was pumped using aperistaltic pump speed of 15 rpm into a beaker containing 1 L water thathad been pre-heated with low pressure steam for 1 min. The cement wasthen added for 2 min with continued steam.

6.25 mg of the LCST compounds Methyl cellulose,Hydroxyethyl-methylcellulose or Hydroxypropy-methylcellulose (or 2230ppm calculated on the content of polyisobutylene in the organic medium)were added in form of 0.25 ml of a 2.5 wt.-% aqueous solution to theaqueous phase prior to pre-heating the water.

100.00 mg of Calcium stearate (or 35700 ppm calculated on the content ofpolyisobutylene in the organic medium) were added in form of 0.2 ml of a50 wt.-% aqueous solution to the aqueous phase prior to pre-heating thewater for comparison.

-   -   or non-LCST compounds mentioned below were added or not prior to        pre-heating the water.

The formation of crumbs was then checked:

FAIL means no formation of discrete polyisobutylene particles butsettlement of a single mass was observed.

PASS means formation of discrete polyisobutylene particles was observed.

The results are given in table 1 below:

TABLE 1 Antiagglomerant: Methyl Hydroxyethyl- Hydroxpropy-Polyisobutylene cellulose methylcellulose methylcellulose Calcium Ex.specification None (5*) (6*) (7*) stearate** 4 1* FAIL PASS PASS PASSFAIL 5 2* FAIL PASS PASS PASS FAIL 6 3* FAIL PASS PASS PASS FAIL 7 4*FAIL PASS PASS PASS FAIL 1*: weight average molecular weight of 340,000,a viscosity average molecular weight of 400,000 and a polydispersity of5.0 2*: weight average molecular weight of 750,000, a viscosity averagemolecular weight of 800,000 and a polydispersity of 5.0 3*: weightaverage molecular weight of 1,100,000, a viscosity average molecularweight of 1,110,000 and a polydispersity of 5.0 4*: weight averagemolecular weight of 2,500,000, a viscosity average molecular weight of2,60,000 and a polydispersity of 5.0 (5*): The methyl cellulose employedhad a solution viscosity at 2 wt.-% solution of 3000-5600 cps, molecularweight Mw of ~90,000, a methoxy substitution of 27.5 □31.5 wt.-% andthus a degree of substitution of around 1.9. (6*): Viscosity 600-1500mPas, 2 wt.-% in water (20□C.), Sigma (7*): Viscosity 2,600 □5,600 cp (2wt.-% in water at 20□C.), H7509, Sigma **For comparison

Cloud point LCST compound [□C.] Method Methyl Cellulose (*5) 39.0 5)Methyl Cellulose (*5) 37.8 4) Hydroxyethyl methyl cellulose (*6) 80.8 5)Hydroxyethyl methyl cellulose (*6) 80.6 4) Hydroxpropyl methyl cellulose(*7) 49.9 4)

The invention claimed is:
 1. A process for preparing an aqueous slurrycomprising a plurality of polyisobutylene particles suspended therein,the process comprising: A) contacting an organic medium comprising: i) apolyisobutylene, and ii) an organic diluent, with an aqueous mediumcomprising a lower critical solution temperature (LCST) compound havinga cloud point of 0 to 100° C.; and B) removing at least partially theorganic diluent, to obtain the aqueous slurry comprising thepolyisobutylene particles, wherein the polyisobutylene particles arediscrete particles having a particle size of between 0.05 mm and 25 mm.2. The process according to claim 1, wherein the LCST compound has acloud point of 0 to 100° C., determined by at least one of the followingmethods: DIN EN 1890 of September 2006, method A; DIN EN 1890 ofSeptember 2006, method C; DIN EN 1890 of September 2006, method E; DINEN 1890 of September 2006, method A wherein the amount of compoundtested is reduced from 1 g per 100 ml of distilled water to 0.05 g per100 ml of distilled water; and DIN EN 1890 of September 2006, method Awherein the amount of compound tested is reduced from 1 g per 100 ml ofdistilled water to 0.2 g per 100 ml of distilled water.
 3. The processaccording to claim 1, wherein the LCST compound has a cloud point of 0to 100° C., determined by at least one of the following methods: DIN EN1890 of September 2006, method A; DIN EN 1890 of September 2006, methodE; and DIN EN 1890 of September 2006, method A wherein the amount ofcompound tested is reduced from 1 g per 100 ml of distilled water to0.05 g per 100 ml of distilled water.
 4. The process according to claim1, wherein the LCST compound has a cloud point of 0 to 100° C.,determined by at least one of the following methods: DIN EN 1890 ofSeptember 2006, method A; DIN EN 1890 of September 2006, method C; andDIN EN 1890 of September 2006, method A wherein the amount of compoundtested is reduced from 1 g per 100 ml of distilled water to 0.05 g per100 ml of distilled water.
 5. The process according to claim 1, whereinthe organic medium comprising the polyisobutylene and the organicdiluent is obtained from a polymerization reaction.
 6. The processaccording to claim 5, wherein the organic medium further comprisesresidual polyisobutylene of the polymerization reaction.
 7. The processaccording claim 1, wherein the aqueous medium further comprises at leastone non-LCST compound selected from the group consisting of ionicsurfactants, non-ionic surfactants, emulsifiers, antiagglomerants, ⋅salts of monovalent metal ions, and salts of multivalent metal ions. 8.The process according to claim 7, wherein the aqueous medium comprises20,000 ppm or less of the non-LCST compounds.
 9. The process accordingto claim 1, wherein the aqueous medium further comprises from 0 to 5,000ppm of at least one non-LCST compound, which is a salt of a monovalentmetal ion, calculated on its metal content and with respect to theamount of polyisobutylene present in the organic medium.
 10. The processaccording to claim 1, wherein the aqueous medium further comprises from0 to 5,000 ppm of at least one non-LOST compound, which is a salt of amultivalent metal ion, calculated on its metal content and with respectto the amount of polyisobutylene present in the organic medium.
 11. Theprocess according to claim 1, wherein the aqueous medium furthercomprises at least one non-LCST compound selected from stearates ofmonovalent metal ions, stearates of multivalent metal ions, palmitatesof monovalent ions, palmitates of multivalent metal ions, oleates ofmonovalent metal ions, and oleates of multivalent metal ions.
 12. Theprocess according to claim 7, wherein the aqueous medium comprises 8,000ppm or less of the non-ionic surfactants with respect to the amount ofpolyisobutylene present in the organic medium.
 13. The process accordingto claim 7, wherein the aqueous medium comprises 70 ppm or less of thesalts of multivalent metal ions calculated on their metal content andwith respect to the amount of polyisobutylene present in the organicmedium.
 14. The process according to claim 7, wherein: the aqueousmedium comprises 550 ppm or less of carboxylic acid salts of multivalentmetal ions calculated on their metal content and with respect to theamount of polyisobutylene present in the organic medium; and thecarboxylic acids have 6 to 30 carbon atoms.
 15. The process according toclaim 7, wherein the aqueous medium is free of carboxylic acid salts ofmultivalent metal ions, wherein the carboxylic acids have 6 to 30 carbonatoms.
 16. The process according to claim 7, wherein the aqueous mediumis free of carboxylic acid salts of monovalent metal ions wherein thecarboxylic acids have 6 to 30 carbon atoms.
 17. The process according toclaim 7, wherein the aqueous medium comprises a least one non-LOSTcompound, which is a monocarboxylic acid salt of a monovalent ormultivalent metal ion.
 18. The process according to claim 7, wherein theaqueous medium comprises of from 0 to 5,000 ppm of: carbonates ofmultivalent metal ions calculated on their metal content and withrespect to the amount of polyisobutylene present in the organic medium;or magnesium carbonate and calcium carbonate calculated on their metalcontent and with respect to the amount of polyisobutylene present in theorganic medium.
 19. The process according to claim 1, wherein theaqueous medium comprises 500 ppm or less of dispersants, emulsifiers,and anti-agglomerants other than LCST compounds.
 20. The processaccording to claim 1, wherein polyisobutylene particles are discreteparticles having a particle size of between 0.1 mm and 25 mm.
 21. Theprocess according to claim 1, wherein polyisobutylene particles have aweight average particle size of from 0.3 to 10.0 mm.
 22. The processaccording to claim 1, wherein the aqueous medium comprises from 1 to2,000 ppm of antioxidants and/or stabilizers, calculated with respect tothe amount of polyisobutylene present in the organic medium.
 23. Theprocess according to claim 1, wherein the viscosity averaged molecularweight (Mv) of the polyisobutylene is in the range of 100 to 3,000kg/mol.
 24. The process according to claim 1, wherein thepolyisobutylene has a polydispersity of 3.0 to 5.5 as measured by theratio of weight average molecular weight to number average molecularweight as determined by gel permeation chromatography.
 25. The processaccording to claim 1, wherein the polyisobutylene has a Mooney viscosityof at least 10 (ML 1+8 at 125° C., ASTM D 1646).
 26. The processaccording to claim 1, wherein the organic medium is obtained by aprocess comprising polymerizing isobutylene within a reaction mediumcomprising an organic diluent and the isobutylene, in the presence of aninitiator system or catalyst, to form the organic medium comprising thepolyisobutylene, the organic diluent, and optionally residualisobutylene.
 27. The process according to claim 26, wherein theisobutylene is present in the reaction medium in an amount of from 0.01wt.-% to 80 wt.-%.
 28. The process according to claim 26, wherein theorganic diluent comprises at least one of a hydrochlorocarbon and ahydrofluorocarbon represented by the formula:CxHyFz,  wherein: x is an integer from 1 to 40 y and z are integers andat least one, or at least one hydrocarbon selected from the groupconsisting of propane, isobutane, pentane, methycyclopentane, isohexane,2-methylpentane, 3-methylpentane, 2-methylbutane, 2,2-dimethylbutane,2,3-dimethylbutane, 2-methylhexane, 3-methylhexane, 3-ethylpentane,2,2-dimethylpentane, 2,3-dimethylpentane, 2,4-dimethylpentane,3,3-dimethyl pentane, 2-methylheptane, 3-ethylhexane,2,5-dimethylhexane, 2,2,4,-trimethylpentane, octane, heptane, butane,ethane, methane, nonane, decane, dodecane, undecane, hexane, methylcyclohexane, cyclopropane, cyclobutane, cyclopentane,methylcyclopentane, 1,1-dimethylcycopentane,cis-1,2-dimethylcyclopentane, trans-1,2-dimethylcyclopentane,trans-1,3-dimethyl-cyclopentane, ethylcyclopentane, cyclohexane,methylcyclohexane, and mixtures thereof.
 29. The process according toclaim 26, wherein the polymerization is carried out as a slurrypolymerization or a solution polymerization.
 30. The process accordingto claim 26, wherein the polymerization is carried out continuously. 31.The process according to claim 26, wherein, in the polymerization, atleast one control agent for the initiator system is employed.
 32. Theprocess according to claim 31, wherein the at least one control agentcomprises ethylene, mono-substituted C₃-C₂₀ monoalkenes, ordi-substituted C₃-C₂₀ monoalkenes.
 33. The process according to claim31, wherein the at least one control agent comprises diisobutylene. 34.The process according to claim 26, wherein the initiator comprisesaluminium trichloride.
 35. The process according to claim 34, whereinwater and/or alcohols are used as a proton source.
 36. The processaccording to claim 26, wherein the temperature in the contacting A) isfrom 10 to 100° C.
 37. The process according to claim 1, wherein theLCST compound is at least one selected from the group consisting of:poly(N-isopropylacrylamide),poly(N-isopropylacrylamide-co-N,N-dimethylacrylamide,poly(N-isopropylacrylamide)-alt-2-hydroxyethylmethacrylatepoly(N-vinylcaprolactam), poly(N,N-diethylacrylamide),poly[2-(dimethylamino)ethyl methacrylate], poly(2-oxazoline)glycopolymers, Poly(3-ethyl-N-vinyl-2-pyrrolidone), hydroxylbutylchitosan, polyoxyethylene (20) sorbitan monostearate, polyoxyethylene(20) sorbitan monolaurate, polyoxyethylene (20) sorbitan monooleate,methyl cellulose, hydroxypropyl cellulose, hydroxyethyl methylcellulose,hydroxypropyl methylcellulose, polyethylene glycol) methacrylates with 2to 6 ethylene glycol units, polyethyleneglycol-co-polypropylene glycols,compounds of formula (I)HO—[—CH2-CH2-O]x-[-CH(CH3)-CH2-O]y-[-CH2-CH2-O]z-H  (I) wherein y=3 to10, x and z=1 to 8, and y+x±z is from 5 to 18,polyethyleneglycol-co-polypropylene glycol, ethoxylatediso-C13H27-alcohols, polyethylene glycol with 4 to 50, polypropyleneglycol with 4 to 30, polyethylene glycol monomethyl, dimethyl, monoethyland diethyl ether with 4 to 50 ethyleneglycol units, polypropyleneglycol monomethyl, dimethyl, monoethyl and diethyl ether with 4 to 50propyleneglycol units, and hydroxyethyl cellulose.
 38. The processaccording to claim 26, wherein the amount of LCST compound(s) present inthe aqueous medium employed in the contacting A) is from 1 to 20,000ppm, with respect to the amount of polyisobutylene present in theorganic medium.
 39. The process according to claim 1, wherein the LCSTcompound has a molecular weight of at least 1,500 g/mol.
 40. The processaccording to claim 26, further comprising: C) separating thepolyisobutylene particles contained in the aqueous slimy obtained in B),to obtain isolated polyisobutylene particles.
 41. The process accordingto claim 40, further comprising: D) drying the isolated polyisobutyleneparticles.
 42. The process according to claim 1, further comprising:shaping of the polyisobutylene particles, to obtain reshapedpolyisobutylene particles.
 43. The process according to claim 22,wherein the antioxidants and/or stabilizers are selected from the groupconsisting of 2,6-di-tert-butyl-4-methyl-phenol,pentaerythrol-tetrakis-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propanoicacid, octadecyl 3,5-di(tert)-butyl-4-hydroxyhydrocinnamate,tert-butyl-4-hydroxy anisole, dimethyl)-1,4-benzenediol,tris(2,4,-di-tert-butylphenyl)phosphate, dioctyldiphenylamine, butylatedproducts of p-cresol and dicyclopentadiene or2,4,6-tri-tert-butylphenol, 2,4,6 tri-isobutylphenol,2-tert-butyl-4,6-dimethylphenol, 2,4-dibutyl-6-ethylphenol,2,4-dimethyl-6-tert-butylphenol, 2,6-di-tert-butylhydroyxytoluol (BHT),2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-4-n-butylphenol,2,6-di-tert-butyl-4-iso-butylphenol, 2,6-dicyclopentyl-4-methylphenol,4-tert-butyl-2,6-dimethylphenol, 4-tert-butyl-2,6-dicyclopentylphenol,4-tert-butyl-2,6-diisopropylphenol, 4,6-di-tert-butyl-2-methylphenol,6-tert-butyl-2,4-dimethylphenol, 2,6-di-tert-butyl-3-methylphenol,4-hydroxymethyl-2,6-di-tert-butylphenol,2,6-di-tert-butyl-4-phenylphenol, 2,6-dioctadecyl-4-methylphenol,2,2′-ethylidene-bis[4,6-di-tert-butylphenol]2,2′-ethylidene-bis[6-tert-butyl-4-isobutylphenol],2,2′-isobutylidene-bis[4,6-dimethyl-phenol],2,2′-methylene-bis[4,6-di-tert-butylphenol],2,2′-methylene-bis[4-methyl-6-(α-methylcyclohexyl)phenol]2,2′-methylene-bis[4-methyl-6-cyclohexylphenol],2,2′-methylene-bis[4-methyl-6-nonylphenol],2,2′-methylene-bis[6-(α,α′-dimethylbenzyl)-4-nonylphenol],2,2′-methylene-bis 6-(α-methylbenzyl)-4-nonylphenol,2,2-methylene-bis[6-cyclohexyl-4-methylphenol],2,2′-methylene-bis[6-tert-butyl-4-ethylphenol],2,2′-methylene-bis[6-tert-butyl-4-methylphenol],4,4′-butylidene-bis[2-tert-butyl-5-methylphenol],4,4′-methylene-bis[2,6-di-tert-butylphenol],4,4′-methylene-bis[6-tert-butyl-2-methylphenol],4,4′-isopropylidene-diphenol, 4,4′-decylidene-bisphenol,4,4′-dodecylidene-bisphenol, 4,4′-(1-methyloctylidene)bisphenol,4,4′-cyclohexylidene-bis(2-methylphenol), 4,4′-cyclohexylidenebisphenol,andpentaerythrol-tetrakis-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propanoicacid.
 44. The process according to claim 1, wherein the LCST compound isat least one selected from the group methyl cellulose, hydroxyethylcellulose, hydroxypropyl cellulose, hydroxyethyl methylcellulose, andhydroxypropyl methylcellulose.